
Although liquefaction technology has been extensively applied, plenty of biomass remains tainted with heavy metals (HMs). A meta-analysis of literature published from 2010 to 2023 was conducted to investigate the effects of liquefaction conditions and biomass characteristics on the remaining ratio and chemical speciation of HMs in biochar, aiming to achieve harmless treatment of biomass contaminated with HMs. The results showed that a liquefaction time of 1–3 h led to the largest HMs remaining ratio in biochar, with the mean ranging from 84.09% to 92.76%, compared with liquefaction times of less than 1 h and more than 3 h. Organic and acidic solvents liquefied biochar exhibited the greatest and lowest HMs remaining ratio. The effect of liquefaction temperature on HMs remaining ratio was not significant. The C, H, O, volatile matter, and fixed carbon contents of biomass were negatively correlated with the HMs remaining ratio, and N, S, and ash were positively correlated. In addition, liquefaction significantly transformed the HMs in biochar from bioavailable fractions (F1 and F2) to stable fractions (F3) (P < 0.05) when the temperature was increased to 280–330 ℃, with a liquefaction time of 1–3 h, and organic solvent as the liquefaction solvent. N and ash in biomass were positively correlated with the residue state (F4) of HMs in biochar and negatively correlated with F1 or F2, while H, O, fixed carbon, and volatile matter were negatively correlated with F4 but positively correlated with F3. Machine learning results showed that the contribution of biomass characteristics to HMs remaining ratio was higher than that of liquefaction factor. The most prominent contribution to the chemical speciation changes of HMs was the characteristics of HMs themselves, followed by ash content in biomass, liquefaction time, and C content. The findings of this meta-analysis contribute to factor selection, modification, and application of liquefied biomass to reducing risks.
Citation: Li Ma, Likun Zhan, Qingdan Wu, Longcheng Li, Xiaochen Zheng, Zhihua Xiao, Jingchen Zou. Optimization of liquefaction process based on global meta-analysis and machine learning approach: Effect of process conditions and raw material selection on remaining ratio and bioavailability of heavy metals in biochar[J]. AIMS Environmental Science, 2024, 11(3): 342-359. doi: 10.3934/environsci.2024016
[1] | Maurizio Verri, Giovanna Guidoboni, Lorena Bociu, Riccardo Sacco . The role of structural viscoelasticity in deformable porous media with incompressible constituents: Applications in biomechanics. Mathematical Biosciences and Engineering, 2018, 15(4): 933-959. doi: 10.3934/mbe.2018042 |
[2] | Fang Wang, Jiaming Wang, Mingxin Li, Jun Hu, Kehua Song, Jianguo Zhang, Yubo Fan . Biomechanical study of the effect of traction on elbow joint capsule contracture. Mathematical Biosciences and Engineering, 2023, 20(12): 21451-21466. doi: 10.3934/mbe.2023949 |
[3] | Oualid Kafi, Nader El Khatib, Jorge Tiago, Adélia Sequeira . Numerical simulations of a 3D fluid-structure interaction model for blood flow in an atherosclerotic artery. Mathematical Biosciences and Engineering, 2017, 14(1): 179-193. doi: 10.3934/mbe.2017012 |
[4] | Christophe Prud'homme, Lorenzo Sala, Marcela Szopos . Uncertainty propagation and sensitivity analysis: results from the Ocular Mathematical Virtual Simulator. Mathematical Biosciences and Engineering, 2021, 18(3): 2010-2032. doi: 10.3934/mbe.2021105 |
[5] | Tran Quang-Huy, Phuc Thinh Doan, Nguyen Thi Hoang Yen, Duc-Tan Tran . Shear wave imaging and classification using extended Kalman filter and decision tree algorithm. Mathematical Biosciences and Engineering, 2021, 18(6): 7631-7647. doi: 10.3934/mbe.2021378 |
[6] | Tuoi Vo, William Lee, Adam Peddle, Martin Meere . Modelling chemistry and biology after implantation of a drug-eluting stent. Part Ⅰ: Drug transport. Mathematical Biosciences and Engineering, 2017, 14(2): 491-509. doi: 10.3934/mbe.2017030 |
[7] | Li Cai, Qian Zhong, Juan Xu, Yuan Huang, Hao Gao . A lumped parameter model for evaluating coronary artery blood supply capacity. Mathematical Biosciences and Engineering, 2024, 21(4): 5838-5862. doi: 10.3934/mbe.2024258 |
[8] | Xu Bie, Yuanyuan Tang, Ming Zhao, Yingxi Liu, Shen Yu, Dong Sun, Jing Liu, Ying Wang, Jianing Zhang, Xiuzhen Sun . Pilot study of pressure-flow properties in a numerical model of the middle ear. Mathematical Biosciences and Engineering, 2020, 17(3): 2418-2431. doi: 10.3934/mbe.2020131 |
[9] | Subhadip Paul, Prasun Kumar Roy . The consequence of day-to-day stochastic dose deviation from the planned dose in fractionated radiation therapy. Mathematical Biosciences and Engineering, 2016, 13(1): 159-170. doi: 10.3934/mbe.2016.13.159 |
[10] | Rebecca Vandiver . Effect of residual stress on peak cap stress in arteries. Mathematical Biosciences and Engineering, 2014, 11(5): 1199-1214. doi: 10.3934/mbe.2014.11.1199 |
Although liquefaction technology has been extensively applied, plenty of biomass remains tainted with heavy metals (HMs). A meta-analysis of literature published from 2010 to 2023 was conducted to investigate the effects of liquefaction conditions and biomass characteristics on the remaining ratio and chemical speciation of HMs in biochar, aiming to achieve harmless treatment of biomass contaminated with HMs. The results showed that a liquefaction time of 1–3 h led to the largest HMs remaining ratio in biochar, with the mean ranging from 84.09% to 92.76%, compared with liquefaction times of less than 1 h and more than 3 h. Organic and acidic solvents liquefied biochar exhibited the greatest and lowest HMs remaining ratio. The effect of liquefaction temperature on HMs remaining ratio was not significant. The C, H, O, volatile matter, and fixed carbon contents of biomass were negatively correlated with the HMs remaining ratio, and N, S, and ash were positively correlated. In addition, liquefaction significantly transformed the HMs in biochar from bioavailable fractions (F1 and F2) to stable fractions (F3) (P < 0.05) when the temperature was increased to 280–330 ℃, with a liquefaction time of 1–3 h, and organic solvent as the liquefaction solvent. N and ash in biomass were positively correlated with the residue state (F4) of HMs in biochar and negatively correlated with F1 or F2, while H, O, fixed carbon, and volatile matter were negatively correlated with F4 but positively correlated with F3. Machine learning results showed that the contribution of biomass characteristics to HMs remaining ratio was higher than that of liquefaction factor. The most prominent contribution to the chemical speciation changes of HMs was the characteristics of HMs themselves, followed by ash content in biomass, liquefaction time, and C content. The findings of this meta-analysis contribute to factor selection, modification, and application of liquefied biomass to reducing risks.
The biomechanical characterization of biological soft tissues was initially developed by Y.C. Fung on his classical biomechanical treatments [1,2]. He was one of the firsts, together with Fronek, to used a ``new kind'' of elasticity to describe the mechanical behavior of the soft tissues [3], they called this new behavior as pseudo-elasticity. A few years later a new generation of researchers continued on this sense, one of the most know is Holzapfel that together with Gasser and Ogden proposed a new constitutive framework for arterial wall mechanics behavior [4], basically based in a non linear elastic theory introduced by Ogden [5]. In 2004 this group of research realized a comparison of a multi-layer structural model for arterial walls applying a Fung type model, i.e. viscoelasticity. They explored the problematic that emerge on the material stability, in the convergence sense and others problems relatives to the viscoelastic formulation, then in 2010 Holzapfel and Ogden proposed a constitutive modeling of arteries [6] that originated a whole new constitutive frame, named hyperelasticity. Based on strain-energy functions and that represents a huge step on the task of arteries biomechanical characterization, and a great variety of progress was developed and published, like the modeling of biomechanical effects originated by an aneurysm [7,8], the 3D modelling of the human aorta [9,10] or the visco/hyperelastic model that simulate the nonlinear dynamics of atherosclerotic coronary arteries used to predict the initiation of heart attack [11,12].
No often it is not the original Fung's propose for modeling arteries biomechanical behavior, he originally describe the mechanical behavior of the artery as a viscoelastic material. In general, this behavior may be imagined as a spectrum with elastic deformation in one limit case and viscous flow in the other, with varying combinations of the two spread over the range between. Thus, valid constitutive equations for viscoelastic behavior embody elastic deformation and viscous flow as special cases and at the same time provide for response patterns that characterize behavior blends of the two. Intrinsically, such equations will involve not only stress and strain, but time-rates of both stress and strain as well [13]. As mentioned before this kind of materials models, has a great inconvenient related with the convergence on the finite element method software, frequently used to solve this mathematical models [8,6,14,15]. To avoid this situation we can use a prony series and the relaxation function, but again to obtain an accurate solution we need to use a large number of prony series that elevates the computer time on the task of solution finding.
At recent times the fractional calculus theory has been used to modeling viscoelastic materials [16,17,18], consequently some researchers used to model biological soft tissues [19,20], like the use of Kelvin-Voigt fractional viscoelastic model employed to determinate the biomechanical properties of the human liver tissue or the pancreas by Wex [21,22], using stress relaxation test to articular cartilage [23], and even the human calcaneal fat pad [24] using fractional derivatives kernels. Recently this material models are used to estimate the biological changes of the mechanical behavior due to the presence of tumors [25]. Craiem et al [26,27,28] use a fractional viscoelastic constitutive model to describe the arterial biomechanics response, using uniaxial relaxation test.
One of the greatest advantages consist on that many of the basic viscoelastic ideas can be introduce within the context of a one-dimensional state of stress. Once the relaxation modulus, the creep compliance and the complex modulus are obtained, its functions can be included by a subroutine on a FEM software, with the necessary geometry restrictions [29] and the viscoelastic relaxation modifications, or by an finite element model specially develop for fractional differential and integral operators [30].
Viscoelastic fractional models have taken a recent boom in the task of modeling the mechanical behaviour of polymers and soft tissues. Due to the fact that the definition of the fractional derivative provide a new formulation to describe the mechanical behaviour of a material that exhibits a behavior that oscillates between the hooke solids model and the Newtonian fluids [31]. That is one of the principal characteristics of the soft tissues.
The circulatory system is basically composed of the heart and blood vessel system. At the time, the blood vessel system are composing of arteries, arterioles and veins. Arteries are basically conform of three internal layers, known as Tunica Intima, Tunica Media and Tunica Externa or Adventicia, with a semi-cylindrical form and mainly compose of collagen, elastin and muscular fibers [32]. In young humans, the intima is an extremely thin layer (80nm) like a membrane separate to the media for a lay of elastin, the media are form of soft muscular cells merge on a collagen and elastin cellular matrix, finally the externa is the thick layer compose of collagen and fibroblasts [33].
This particular conformation brings the artery a mixed mechanical material behavior know as viscoelasticity [1]. In general, viscoelastic behavior may be imagined as a spectrum with elastic deformation as one limiting case and viscous flow the other extreme case, with varying combinations of the two spread over the range between. Thus, valid constitutive equations for viscoelastic behavior embody elastic deformation and viscous flow as special cases and at the same time provide for response patterns that characterize behavior blends of the two.
Intrinsically, such equations will involve not only stress and strain, but time-rates of both stress and strain as well [13].
We first develop the mathematical and mechanical background that support the present research, with the finality that those readers interested on the topics be familiarized with the basic concepts.
Linear viscoelasticity is a common theory to approximate the time-dependent behaviour of polymers, and materials that exhibit similar characteristics at relatively low temperatures and stress.
The development of the mathematical theory of linear viscoelasticity is based on the principle that the mechanical stress on a certain period of time is directly proportional to the strain rate. In that way, if we have that stress and stress rate are infinitesimal and the stress-strain relation depend on time, that relationship can be expressed by a differential equation with constant coefficients.
The stress-strain relationship can be described, assuming that the Maxwell-Boltzmann principle are satisfied, by the constitutive equation:
σ(t)=t∫−∞G(t−ξ)dε(ξ)dξdξ | (2.1) |
or
ε(t)=t∫−∞J(t−ξ)dσ(ξ)dξdξ | (2.2) |
were G(t) and J(t) are the stress relaxation modulus and the creep compliance respectively. These important functions are commonly employing on material characterization, and are describing above.
The creep test consists of instantaneously subjecting the material to a simple shear stress of magnitude σ0 and maintaining that stress constant thereafter while measuring the shear strain as a function of time. The resulting strain is called the creep. In the stress relaxation test, and instantaneous shear strain of magnitude ε0 is imposed on the material sample and maintained at the value while the resulting stress, is recorded as a function of time. The decrease in the stress values over the duration of the test is referred to as the stress relaxation.
The behavior of viscoelastic materials when are subject to harmonic stress or strain is an important part of the theory of viscoelasticity and sustains a fundamental part of the research. Cyclic experiments are used to identify the mechanical behavior of the material and to determine the values of the elastic and viscous plots of this, maintaining a balance between complexity and simulation capacity of the phenomena. Data processing could be carried out in the same way for a non-cyclic signal, but it would have to be extensive in time to have enough information to fit the model and its processing would be complex.
Consider the response of the material, when is applying a harmonic shear strain of frequency ω as:
ε(t)=ε0sin(ωt) | (2.3) |
At the same time the strain rate changes with the same frequency ω with a translation ϕ with respect to the stress,
σ(t)=σ0sin(ωt+ϕ) | (2.4) |
replacing equation 2.4 on equation 2.1, will be able to obtain the constitutive equation:
σ(t)=ε0(G′sin(ωt)+G′′cos(ωt)) | (2.5) |
with
G′(ω)=ω∫∞0G(t−ξ)sin(ω(t−ξ)) d(t−ξ) | (2.6) |
and
G′′(ω)=ω∫∞0G(t−ξ)cos(ω(t−ξ)) d(t−ξ) | (2.7) |
where G′(ω), G′′(ω) are known as the storage and loss modulus respectively. Expressing the harmonic functions on the complex plane we have
σ∗ε∗=G∗=G′+iG′′ | (2.8) |
where G∗ are define as the complex modulus, and is simply the norm of the loss and storage modulus contributions.
At recent times the fractional calculus theory, has used to formulate a wide range of new models on the biomechanics and mechanobiology field [20], the fractional differential and integral equations have a great development specially in the task of characterize the mechanical behavior of soft tissues [19] like the brain [25], liver [21], arteries [27,28,34] and even the human calcaneal fat pad [24].
We now consider the fractional generalization of the Standard Linear Solid (FSLS), show on Figure 1. For this purpose, is sufficient to replace the first order derivative with the fractional Caputo [35] derivative of order ν∈(0,1) in their constitutive equations. We obtain the following stress-strain relationship and the corresponding material functions are described latter.
The equation 2.9 is basically the same that in integer order, but here we replace the first derivative with the Caputo fractional differential operator
∗0Dνtσ(t)+e2ησ(t)=(e1+e2) ∗0Dνtε(t)+e1e2ηε(t) | (2.9) |
applying the Laplace transform to both sides of the equation 2.9 we obtain,
[sν+e2η]ˉσ(s)=[(e1+e2)sν+(e1e2η)]ˉε(s) | (2.10) |
solving for ˉε(s)
ˉε(s)=sν+α(e1+e2)sν+βˉσ(s) | (2.11) |
where α=e2η and β=e1e2η, applying the Laplace inverse transform and the convolution law, we have the analytical solution for FSLS model,
ε(t)=[δ(t)e1+e2+1(e1+e2)t∞∑n=1(−ζtν)nΓ(nν)+αtν−1e1+e2∞∑n=0(−ζtν)nΓ(ν(n+1))]∗σ(t) | (2.12) |
where δ(t) is the traditional Dirac's delta, ∗ is a convolution and ζ=βe1.
Now we proceed to the implementation of the FSLS to the artery modeling process, first we describe the relaxation modulus, the creep compliance and the complex modulus, all necessary for the mechanical one dimensional characterization on the material [36]. Next we briefly shown the process to the creation of the vectorized image and the exportation to CAD software that aloud to be treating like a solid with the mechanical properties and restrictions.
The values of the constants used on the research are taking for experimental creep relaxation test realized on [27] and are e1=0.68, e2=0.39, η=2.14 and ν=0.23. Now we describe the material model functions like the relaxation modulus, creep compliance and complex modulus. The relaxation modulus for the FSLS has the form,
G(t)=e1+e2⋅Eν[−(e2ηtν)] | (3.1) |
where
Eν,φ[(−e2ηtν)]=∞∑n=0(−e2ηtν)nΓ(νn+φ) | (3.2) |
is the Mittag-Lleffler function [20] with ν,φ∈R+ and e1η∈R. On Figure 2 are plot the relaxation modulus function for four fractional order values, and the constants value mentioned before.
In the same way, we obtain and plot the creep compliance function, for different fractional values ν, the creep compliance function J(t) have the form:
J(t)=μ+(1e1−μ)[1−Eν[−(e1e2μηtν)]] | (3.3) |
where μ=1e1+e2.
The complex modulus, present on Figure 2, complete the set of basic functions required for the mechanical characterization.
The axial dicom images are used to obtain a 2D geometry for every one of the slices, taking care on identify properly witch points generate each one of the segments, to do that its necessary to establish a consistent metric respect the patient's measure and an appropriate Hounsfield scale. The coordinates are localized and saved on a csv file. Now a spline curve can be generated through the geometric pattern, this way the cloud of points on each slice are limit by a close contour. This processes are repeat for the creation of each one of the slices and each one of the respective segments of the artery, the intima, the media and the adventicia. This procedure is illustrated in the left side of Figure 3.
Once the geometric patterns are due in all the set of axial images. Again a spline is applied to the set of slices, now to generate the 3D artery segment representation. Therefore this geometry is save on.iges format and export to CAD software, for the three layer solid representation. Now this is able to function properly in finite element method analysis software as see on the right side of Figure 3.
Like in all the others numerical methods, the precision of the method consist basically on the size of the step. If the element is the sufficient small the method converge to the require solution with minimal error. For that reason we need to do the finest mesh that can be possible in function that the processor is able to work.
The artery have a total volume of 0.2865 cm3 and are meshed with 654,977 eight node brick elements, i.e. the mesh consist on 2,000,000 element for cubic centimeter. This size of the mesh it's necessary to are secure that the finite element method converge to the require solution, because in other way the software can enter on a infinity loop or brings an non sense solution, from this number of elements the convergence is the same. The mechanical properties of the three segments are shown in table 1.
Omega g∗ | Omega g∗ | Omega k∗ | Omega k∗ | Frecuency |
real | imag | real | imag | Hz |
2.02E-11 | 4.32E-06 | 2.18E-11 | 3.94E-06 | 0.001 |
2.02E-09 | 4.32E-05 | 2.18E-09 | 0.000038 | 0.01 |
2.02E-07 | 0.000432 | 2.18E-07 | 0.000389 | 0.1 |
2.01E-05 | 0.004323 | 2.17E-05 | 0.003897 | 1.0 |
-0.056137 | 0.166779 | 0.116504 | -0.018474 | 23.0 |
0.113203 | 0.267329 | 0.313763 | 0.479758 | 100.0 |
0.989947 | 0.032453 | 0.514424 | -0.426401 | 350.0 |
The finite element method software are configured to realize the viscoelastic material routine by the property implementation of the frequency data test. Once the data are introduced on the software, we need to apply a load on the internal intima surface, simulating the pressure caused by a blood flow rate of 120/80 mmHg as shown on Figure 4 [37], and a constant load pressure on the exterior externa surface due to muscular compression originated by the muscles that round the artery, the temperature of the body will be consider constant, the extremes of the aorta are fixed by a constraint option and for last the interaction between the layers is set as a tie restriction.
The result of the solid's deformation is shown on top of Figure 5, where the simulation exhibit a tendency or pattern of the deformation route and not necessarily the real deformation, the behavior showed by the artery concord with those founded and predicted previously by [24,19].
In Figure 5 the efforts of von Mises also known as equivalent efforts are show since these are obtained from a relationship that combines the main efforts in an equivalent effort that can be used to compare with the effort of transfer of the analyzed material. The values of the von Mises stress obtained in this research are consistent with previously developed investigations in the experimental field where values of 0.213 MPa for blood pressure of 120mmHg are reported, which coincides with the results obtained by simulation using the viscoelastic fractional method.
In previous research it is founded that the area where the maximum stress values are presented, is distributed in the intimate layer of the artery and is located in the place where it changes its geometry, that is, where there is a change in artery curvature [40].
Finally, Figure 6 shows the distribution of internal pressure caused by blood flow where 0.03MPa pressure zones are identified in general and some 0.098MP maximum pressure zones, which is consistent with the results previously published by Holzapfel [41]
The results obtained were compared with experiments carried out in 2014, where fractional models have been used to characterize various soft tissues, showing that the parameters determined in the research are within the range of those previously found [24,25,19].
The stress distribution and the maximum values funded in the research concords with those previously reported by Holzapfel [40,41], using an hyperelastic model with prony series.
First we obtained the reconstruction of a segment of the aortic artery based on medical images obtained from a computerized axial tomography scanner, using the Hounsfield scale we could identify each of its three constituent layers (intima, media and adventitia). In addition, the process of exporting the medical image in a vectorized geometry was carried out with which it was possible to export to a solid form, that could be manipulated in a finite element software.
Compared with previous works where simulations of the biomechanical effects of the artery were performed using geometric idealizations, considering the layers of the artery as perfect cylinders, it was observed that when doing this what is had for the state of stress consists of a distribution perfectly symmetrical of the stresses, and in the case of the state of deformations in the same way there is a constant deformation in all directions of the solid. However, the geometry of the artery does not consist of a series of cylinders, so it was found in the development of the investigation that the distribution of stress has its local maximum, speaking of von Mises stress, at the point where the artery presents a change in curvature that generates a great deformation at that point, unlike to a uniform deformation, will end up affecting more to one end of the artery.
In this paper we shown that viscoelastic fractional models represents properly the mechanical behavior of the aortic artery, based on a uniaxial simple model.
In addition, it has been proven that with the viscoelastic fractional model, values similar to those previously provided in the literature are obtained without the use of prony series, which considerably reduces the computation time required.
We want to thankful the institutions that supported the present research project, Tecnológico Nacional de México / Instituto Tecnológico Superior de Cajeme, the Biomechanics Investigation Group from Universidad Tecnológica de la Habana, La Habana, Cuba and the Pontificia Universidad Católica de Valparaíso, Chile.
All authors declare no conflicts of interest in this paper.
[1] |
Wang X, Li C, Zhang B, et al. (2016) Migration and risk assessment of heavy metals in sewage sludge during hydrothermal treatment combined with pyrolysis. Bioresour Technol 221: 560–567. https://doi.org/10.1016/j.biortech.2016.09.069 doi: 10.1016/j.biortech.2016.09.069
![]() |
[2] |
Sharma HB, Sarmah AK, Dubey B (2020) Hydrothermal carbonization of renewable waste biomass for solid biofuel production: A discussion on process mechanism, the influence of process parameters, environmental performance and fuel properties of hydrochar. Renew Sust Energ Rev 123: 109761. https://doi.org/10.1016/j.rser.2020.109761 doi: 10.1016/j.rser.2020.109761
![]() |
[3] |
Castro JS, Assemany PP, Carneiro ACO, et al. (2021) Hydrothermal carbonization of microalgae biomass produced in agro-industrial effluent: Products, characterization and applications. Sci Total Environ 768: 144480. https://doi.org/10.1016/j.scitotenv.2020.144480 doi: 10.1016/j.scitotenv.2020.144480
![]() |
[4] |
Wang H, Yang Z, Li X, et al. (2020) Distribution and transformation behaviors of heavy metals and phosphorus during hydrothermal carbonization of sewage sludge. Environ Sci Pollut R 27: 17109–17122. https://doi.org/10.1007/s11356-020-08098-4 doi: 10.1007/s11356-020-08098-4
![]() |
[5] |
Wang JX, Chen SW, Lai FY, et al. (2020) Microwave-assisted hydrothermal carbonization of pig feces for the production of hydrochar. J Supercrit Fluid 162: 104858. https://doi.org/10.1016/j.supflu.2020.104858 doi: 10.1016/j.supflu.2020.104858
![]() |
[6] |
Tsai WT, Liu SC, Chen HR, et al. (2012) Textural and chemical properties of swine-manure-derived biochar pertinent to its potential use as a soil amendment. Chemosphere 89: 198–203. https://doi.org/10.1016/j.chemosphere.2012.05.085 doi: 10.1016/j.chemosphere.2012.05.085
![]() |
[7] |
Chen H, Wang X, Lu X, et al. (2018) Hydrothermal conversion of Cd-enriched rice straw and Cu-enriched Elsholtzia splendens with the aims of harmless treatment and resource reuse. Ind Eng Chem Res 57: 15683–15689. https://doi.org/10.1021/acs.iecr.8b04378 doi: 10.1021/acs.iecr.8b04378
![]() |
[8] |
Xu X, Wu Y, Wu X, et al. (2022) Effect of physicochemical properties of biochar from different feedstock on remediation of heavy metal contaminated soil in mining area. Surf Interfaces 32: 102058. https://doi.org/10.1016/j.surfin.2022.102058 doi: 10.1016/j.surfin.2022.102058
![]() |
[9] |
Celletti S, Bergamo A, Benedetti V, et al. (2021) Phytotoxicity of hydrochars obtained by hydrothermal carbonization of manure-based digestate. J Environ. Manage 280: 111635. https://doi.org/10.1016/j.jenvman.2020.111635 doi: 10.1016/j.jenvman.2020.111635
![]() |
[10] |
Zhang Y, Liu S, Niu L, et al. (2023) Sustained and efficient remediation of biochar immobilized with Sphingobium abikonense on phenanthrene-copper co-contaminated soil and microbial preferences of the bacteria colonized in biochar. Biochar 5. https://doi.org/10.1007/s42773-023-00241-x doi: 10.1007/s42773-023-00241-x
![]() |
[11] |
Li X, Li R, Zhan M, et al. (2024) Combined magnetic biochar and ryegrass enhanced the remediation effect of soils contaminated with multiple heavy metals. Environ Int 185: 108498. https://doi.org/10.1016/j.envint.2024.108498 doi: 10.1016/j.envint.2024.108498
![]() |
[12] |
Li H, Yuan X, Zeng G, et al. (2010) The formation of bio-oil from sludge by deoxy-liquefaction in supercritical ethanol. Bioresource Technol 101: 2860–2866. https://doi: 10.1016/j.biortech.2009.10.084 doi: 10.1016/j.biortech.2009.10.084
![]() |
[13] |
Jiang H, Yan R, Cai C, et al. (2021) Hydrothermal liquefaction of Cd-enriched Amaranthus hypochondriacus L. in ethanol-water co-solvent: Focus on low-N bio-oil and heavy metal/metal-like distribution. Fuel 303: 121235. https://doi.org/10.1016/j.fuel.2021.121235 doi: 10.1016/j.fuel.2021.121235
![]() |
[14] |
Lee J, Park KY (2021) Conversion of heavy metal-containing biowaste from phytoremediation site to value-added solid fuel through hydrothermal carbonization. Environ Pollut 269: 116127. https://doi.org/10.1016/j.envpol.2020.116127 doi: 10.1016/j.envpol.2020.116127
![]() |
[15] |
Fang J, Gao B, Chen J, et al. (2015) Hydrochars derived from plant biomass under various conditions: Characterization and potential applications and impacts. Chem Eng J 267: 253–259. https://doi.org/10.1016/j.cej.2015.01.026 doi: 10.1016/j.cej.2015.01.026
![]() |
[16] |
Reza MT, Lynam JG, Uddin MH, et al. (2013) Hydrothermal carbonization: Fate of inorganics. Biomass Bioenergy 49: 86–94. https://doi.org/10.1016/j.biombioe.2012.12.004 doi: 10.1016/j.biombioe.2012.12.004
![]() |
[17] |
Lang Q, Guo Y, Zheng Q, et al. (2018) Co-hydrothermal carbonization of lignocellulosic biomass and swine manure: Hydrochar properties and heavy metal transformation behavior. Bioresource Technol 266: 242–248. https://doi.org/10.1016/j.biortech.2018.06.084 doi: 10.1016/j.biortech.2018.06.084
![]() |
[18] |
Fu H, Wang B, Wang H, et al. (2022) Assessment of livestock manure-derived hydrochar as cleaner products: Insights into basic properties, nutrient composition, and heavy metal content. J Clean Prod 330: 129820. https://doi.org/10.1016/j.jclepro.2021.129820 doi: 10.1016/j.jclepro.2021.129820
![]() |
[19] |
Ren J, Wang F, Zhai Y, et al. (2017) Effect of sewage sludge hydrochar on soil properties and Cd immobilization in a contaminated soil. Chemosphere 189: 627–633. https://doi.org/10.1016/j.chemosphere.2017.09.102 doi: 10.1016/j.chemosphere.2017.09.102
![]() |
[20] |
Peng N, Li Y, Liu T, et al. (2017) Polycyclic aromatic hydrocarbons and toxic heavy metals in municipal solid waste and corresponding hydrochars. Energ Fuel 31: 1665–1671. https://doi.org/10.1021/acs.energyfuels.6b02964 doi: 10.1021/acs.energyfuels.6b02964
![]() |
[21] |
Sun Y, Gao B, Yao Y, et al. (2014) Effects of feedstock type, production method, and pyrolysis temperature on biochar and hydrochar properties. Chem Eng J 240: 574–578. http://dx.doi.org/10.1016/j.cej.2013.10.081 doi: 10.1016/j.cej.2013.10.081
![]() |
[22] |
Zhou X, Zhao J, Chen M, et al. (2022) Influence of catalyst and solvent on the hydrothermal liquefaction of woody biomass. Bioresource Technol 346: 126354. https://doi.org/10.1016/j.biortech.2021.126354 doi: 10.1016/j.biortech.2021.126354
![]() |
[23] |
Hassan M, Liu Y, Naidu R, et al. (2020) Influences of feedstock sources and pyrolysis temperature on the properties of biochar and functionality as adsorbents: A meta-analysis. Sci Total Environ 744: 140714. https://doi.org/10.1016/j.scitotenv.2020.140714 doi: 10.1016/j.scitotenv.2020.140714
![]() |
[24] |
Li H, Lu J, Zhang Y, et al. (2018) Hydrothermal liquefaction of typical livestock manures in China: Biocrude oil production and migration of heavy metals. J Anal Appl Pyrol 135: 133–140. https://doi.org/10.1016/j.jaap.2018.09.010 doi: 10.1016/j.jaap.2018.09.010
![]() |
[25] |
Zhang J, Wang Y, Wang X, et al. (2022) Hydrothermal conversion of Cd/Zn hyperaccumulator (Sedum alfredii) for heavy metal separation and hydrochar production. J Hazard Mater 423: 127122. https://doi.org/10.1016/j.jhazmat.2021.127122 doi: 10.1016/j.jhazmat.2021.127122
![]() |
[26] |
Wang YJ, Yu Y, Huang HJ, et al. (2022) Efficient conversion of sewage sludge into hydrochar by microwave-assisted hydrothermal carbonization. Sci Total Environ 803: 149874. https://doi.org/10.1016/j.scitotenv.2021.149874 doi: 10.1016/j.scitotenv.2021.149874
![]() |
[27] |
Song C, Shan S, Muller K, et al. (2018) Characterization of pig manure-derived hydrochars for their potential application as fertilizer. Environ Sci Pollut R 25: 25772–25779. https://doi.org/10.1007/s11356-017-0301-y doi: 10.1007/s11356-017-0301-y
![]() |
[28] |
Shafizadeh A, Shahbeig H, Nadian MH, et al. (2022) Machine learning predicts and optimizes hydrothermal liquefaction of biomass. Chem Eng J 445. https://doi.org/10.1016/j.cej.2022.136579 doi: 10.1016/j.cej.2022.136579
![]() |
[29] |
Luutu H, Rose MT, McIntosh S, et al. (2021) Plant growth responses to soil-applied hydrothermally-carbonised waste amendments: A meta-analysis. Plant Soil 472: 1–15. https://doi.org/10.1007/s11104-021-05185-4 doi: 10.1007/s11104-021-05185-4
![]() |
[30] |
Zhang S, Wei L, Trakal L, et al. (2024) Pyrolytic and hydrothermal carbonization affect the transformation of phosphorus fractions in the biochar and hydrochar derived from organic materials: A meta-analysis study. Sci Total Environ 906: 167418. https://doi.org/10.1016/j.scitotenv.2023.167418 doi: 10.1016/j.scitotenv.2023.167418
![]() |
[31] |
Lyu C, Li X, Yuan P, et al. (2021) Nitrogen retention effect of riparian zones in agricultural areas: A meta-analysis. J Clean Prod 315: 128143. https://doi.org/10.1016/j.jclepro.2021.128143 doi: 10.1016/j.jclepro.2021.128143
![]() |
[32] |
Sun G, Sun M, Du L, et al. (2021) Ecological rice-cropping systems mitigate global warming–A meta-analysis. Sci Total Environ 789: 147900. https://doi.org/10.1016/j.scitotenv.2021.147900 doi: 10.1016/j.scitotenv.2021.147900
![]() |
[33] |
Liu C, Bol R, Ju X, et al. (2023) Trade-offs on carbon and nitrogen availability lead to only a minor effect of elevated CO2 on potential denitrification in soil. Soil Biol Biochem 176: 108888. https://doi.org/10.1016/j.soilbio.2022.108888 doi: 10.1016/j.soilbio.2022.108888
![]() |
[34] |
Zeng X, Xiao Z, Zhang G, et al. (2018) Speciation and bioavailability of heavy metals in pyrolytic biochar of swine and goat manures. J Anal Appl Pyrol 132: 82–93. https://doi.org/10.1016/j.jaap.2018.03.012 doi: 10.1016/j.jaap.2018.03.012
![]() |
[35] |
Hu B, Xue J, Zhou Y, et al. (2020) Modelling bioaccumulation of heavy metals in soil-crop ecosystems and identifying its controlling factors using machine learning. Environ Pollut 262: 114308. https://doi.org/10.1016/j.envpol.2020.114308 doi: 10.1016/j.envpol.2020.114308
![]() |
[36] |
Tang Q, Chen Y, Yang H, et al. (2021) Machine learning prediction of pyrolytic gas yield and compositions with feature reduction methods: Effects of pyrolysis conditions and biomass characteristics. Bioresource Technol 339: 125581. https://doi.org/10.1016/j.biortech.2021.125581 doi: 10.1016/j.biortech.2021.125581
![]() |
[37] |
Li H, Wu Y, Liu S, et al. (2022) Decipher soil organic carbon dynamics and driving forces across China using machine learning. Global Change Biol 28: 3394–3410. https://doi.org/10.1111/gcb.16154 doi: 10.1111/gcb.16154
![]() |
[38] |
Selvam SM, Balasubramanian P (2022) Influence of biomass composition and microwave pyrolysis conditions on biochar yield and its properties: A machine learning approach. BioEnerg Res 16: 138–150. https://doi.org/10.1007/s12155-022-10447-9 doi: 10.1007/s12155-022-10447-9
![]() |
[39] |
Zhang W, Chen Q, Chen J, et al. (2023) Machine learning for hydrothermal treatment of biomass: A review. Bioresource Technol 370: 128547. https://doi.org/10.1016/j.biortech.2022.128547 doi: 10.1016/j.biortech.2022.128547
![]() |
[40] |
Chen Y, Dong L, Miao J, et al. (2019) Hydrothermal liquefaction of corn straw with mixed catalysts for the production of bio-oil and aromatic compounds. Bioresource Technol 294: 122148. https://doi.org/10.1016/j.biortech.2019.122148 doi: 10.1016/j.biortech.2019.122148
![]() |
[41] |
Chen H, Wang X, Lyu X, et al. (2019) Hydrothermal conversion of the hyperaccumulator Sedum alfredii Hance for efficiently recovering heavy metals and bio-oil. J Environ Chem Eng 7. https://doi.org/10.1016/j.jece.2019.103321 doi: 10.1016/j.jece.2019.103321
![]() |
[42] |
Chi T, Zuo J, Liu F (2017) Performance and mechanism for cadmium and lead adsorption from water and soil by corn straw biochar. Front Env Sci Eng 11. https://doi.org/10.1007/s11783-017-0921-y doi: 10.1007/s11783-017-0921-y
![]() |
[43] |
He C, Zhang Z, Xie C, et al. (2021) Transformation behaviors and environmental risk assessment of heavy metals during resource recovery from Sedum plumbizincicola via hydrothermal liquefaction. J Hazard Mater 410: 124588. https://doi.org/10.1016/j.jhazmat.2020.124588 doi: 10.1016/j.jhazmat.2020.124588
![]() |
[44] |
Lu J, Watson J, Zeng J, et al. (2018) Biocrude production and heavy metal migration during hydrothermal liquefaction of swine manure. Process Saf Environ 115: 108–115. https://doi.org/10.1016/j.psep.2017.11.001 doi: 10.1016/j.psep.2017.11.001
![]() |
[45] |
Chen H, Zhai Y, Xu B, et al. (2014) Fate and risk assessment of heavy metals in residue from co-liquefaction of Camellia oleifera cake and sewage sludge in supercritical ethanol. Bioresource Technol 167: 578–581. https://doi.org/10.1016/j.biortech.2014.06.048 doi: 10.1016/j.biortech.2014.06.048
![]() |
[46] |
Xiao XF, Chang YC, Lai FY, et al. (2020) Effects of rice straw/wood sawdust addition on the transport/conversion behaviors of heavy metals during the liquefaction of sewage sludge. J Environ Manage 270: 110824. https://doi.org/10.1016/j.jenvman.2020.110824 doi: 10.1016/j.jenvman.2020.110824
![]() |
[47] |
Xiao Z, Yuan X, Jiang L, et al. (2015) Energy recovery and secondary pollutant emission from the combustion of co-pelletized fuel from municipal sewage sludge and wood sawdust. Energy 91: 441–450. https://doi.org/10.1016/j.energy.2015.08.077 doi: 10.1016/j.energy.2015.08.077
![]() |
[48] |
Wang L, Chang Y, Liu Q (2019) Fate and distribution of nutrients and heavy metals during hydrothermal carbonization of sewage sludge with implication to land application. J Clean Prod 225: 972–983. https://doi.org/10.1016/j.jclepro.2019.03.347 doi: 10.1016/j.jclepro.2019.03.347
![]() |
[49] |
Alipour M, Asadi H, Chen C, et al. (2021) Bioavailability and eco-toxicity of heavy metals in chars produced from municipal sewage sludge decreased during pyrolysis and hydrothermal carbonization. Ecol Eng 162. https://doi.org/10.1016/j.ecoleng.2021.106173 doi: 10.1016/j.ecoleng.2021.106173
![]() |
[50] |
Shao J, Yuan X, Leng L, et al. (2015) The comparison of the migration and transformation behavior of heavy metals during pyrolysis and liquefaction of municipal sewage sludge, paper mill sludge, and slaughterhouse sludge. Bioresource Technol 198: 16–22. https://doi.org/10.1016/j.biortech.2015.08.147 doi: 10.1016/j.biortech.2015.08.147
![]() |
[51] |
Wei S, Zhu M, Fan X, et al. (2019) Influence of pyrolysis temperature and feedstock on carbon fractions of biochar produced from pyrolysis of rice straw, pine wood, pig manure and sewage sludge. Chemosphere 218: 624–631. https://doi.org/10.1016/j.chemosphere.2018.11.177 doi: 10.1016/j.chemosphere.2018.11.177
![]() |
[52] |
Huang HJ, Yuan XZ (2016) The migration and transformation behaviors of heavy metals during the hydrothermal treatment of sewage sludge. Bioresource Technol 200: 991–998. https://doi.org/10.1016/j.biortech.2015.10.099 doi: 10.1016/j.biortech.2015.10.099
![]() |
[53] |
Yuan X, Leng L, Huang H, et al. (2015) Speciation and environmental risk assessment of heavy metal in bio-oil from liquefaction/pyrolysis of sewage sludge. Chemosphere 120: 645–652. https://doi.org/10.1016/j.chemosphere.2014.10.010 doi: 10.1016/j.chemosphere.2014.10.010
![]() |
[54] |
Chen S, Chen L, Wang D, et al. (2022) Low pe+pH induces inhibition of cadmium sulfide precipitation by methanogenesis in paddy soil. J Hazard Mater 437: 129297. https://doi.org/10.1016/j.jhazmat.2022.129297 doi: 10.1016/j.jhazmat.2022.129297
![]() |
[55] |
Sun FS, Yu GH, Ning JY, et al. (2020) Biological removal of cadmium from biogas residues during vermicomposting, and the effect of earthworm hydrolysates on Trichoderma guizhouense sporulation. Bioresource Technol 312: 123635. https://doi.org/10.1016/j.biortech.2020.123635 doi: 10.1016/j.biortech.2020.123635
![]() |
[56] |
Sun FS, Yu GH, Polizzotto ML, et al. (2019) Toward understanding the binding of Zn in soils by two-dimensional correlation spectroscopy and synchrotron-radiation-based spectromicroscopies. Geoderma 337: 238–245. https://doi.org/10.1016/j.geoderma.2018.09.032 doi: 10.1016/j.geoderma.2018.09.032
![]() |
1. | Qiyin Lv, Yuan Zhang, Ping He, Yao Chen, Yiwen Wang, Negative Poisson’s ratio artificial blood vessel skeleton multi-objective optimization design and numerical modelling, 2025, 0954-4062, 10.1177/09544062241312888 |
Omega g∗ | Omega g∗ | Omega k∗ | Omega k∗ | Frecuency |
real | imag | real | imag | Hz |
2.02E-11 | 4.32E-06 | 2.18E-11 | 3.94E-06 | 0.001 |
2.02E-09 | 4.32E-05 | 2.18E-09 | 0.000038 | 0.01 |
2.02E-07 | 0.000432 | 2.18E-07 | 0.000389 | 0.1 |
2.01E-05 | 0.004323 | 2.17E-05 | 0.003897 | 1.0 |
-0.056137 | 0.166779 | 0.116504 | -0.018474 | 23.0 |
0.113203 | 0.267329 | 0.313763 | 0.479758 | 100.0 |
0.989947 | 0.032453 | 0.514424 | -0.426401 | 350.0 |
Omega g∗ | Omega g∗ | Omega k∗ | Omega k∗ | Frecuency |
real | imag | real | imag | Hz |
2.02E-11 | 4.32E-06 | 2.18E-11 | 3.94E-06 | 0.001 |
2.02E-09 | 4.32E-05 | 2.18E-09 | 0.000038 | 0.01 |
2.02E-07 | 0.000432 | 2.18E-07 | 0.000389 | 0.1 |
2.01E-05 | 0.004323 | 2.17E-05 | 0.003897 | 1.0 |
-0.056137 | 0.166779 | 0.116504 | -0.018474 | 23.0 |
0.113203 | 0.267329 | 0.313763 | 0.479758 | 100.0 |
0.989947 | 0.032453 | 0.514424 | -0.426401 | 350.0 |