Enhanced adsorption of Pb(II) onto modified hydrochar: Modeling and mechanism analysis

Yu, Xilong; Yang, Tianxue; Zhu, Ning; Dong, Li; Chen, Zeliang; Lang, Qianqian; Liu, Zhengang; Jiao, Wentao

doi:10.1016/j.biortech.2019.121593

Cited by 147 publications

(48 citation statements)

References 37 publications

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“…The adsorption isotherm can reflect the affinity of the adsorbate for the adsorbent and can be used to describe the interaction between the adsorbate and the adsorbent [45]. The adsorption isotherms of Cd 2+ solutions after adding biochar with different initial concentrations are shown in Figure 8.…”

Section: Analysis Of Isothermal Adsorptionmentioning

confidence: 99%

Removal of Aquatic Cadmium Ions Using Thiourea Modified Poplar Biochar

Zhu

Liang

et al. 2020

Water

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Removal of aquatic cadmium ions using biochar is a low-cost method, but the results are usually not satisfactory. Modified biochar, which can be a low-cost and efficient material, is urgently required for Cd-polluted water and soil remediation. Herein, poplar bark (SB) and poplar sawdust (MB) were used as raw materials to prepare modified biochar, which is rich in N- and S- containing groups, i.e., TSBC-600 and TMBC-600, using a co-pyrolysis method with thiourea. The adsorption characteristics of Cd2+ in simulated wastewater were explored. The results indicated that the modification optimized the surface structure of biochar, Cd2+ adsorption process by both TSBC-600 and TMBC-600 was mainly influenced by the initial pH, biochar dosage, and contact time, sthe TSBC-600 showed a higher adsorption capacity compared to TMBC-600 under different conditions. The Langmuir adsorption isotherm model and pseudo-second-order kinetic model were more consistent with the adsorption behavior of TSBC-600 and TMBC-600 to Cd2+, the maximum adsorption capacity of TSBC-600 and TMBC-600 calculated by the Langmuir adsorption isotherm model was 19.998 mg/g and 9.631 mg/g, respectively. The modification method for introducing N and S into biochar by the co-pyrolysis of biomass and thiourea enhanced the removal rate of aquatic cadmium ions by biochar.

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Section: Analysis Of Isothermal Adsorptionmentioning

confidence: 99%

Removal of Aquatic Cadmium Ions Using Thiourea Modified Poplar Biochar

Zhu

Liang

et al. 2020

Water

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“…The DFT simulations summarized in Figure 3 explain that alkali treatment removes the proton to activate the sorption capacity of glucose hydrochar. Physically, the proton is more tightly bonded to the carboxylate group than the metal cations, owing to the differences in ionic radii and the strong effect of ion-ion distance on the strength of electrostatic interactions [94]. Similarly, the differences observed between potassium and sodium can be ascribed to their relative ionic radii.…”

Section: Dft Simulations Of the Metal-carboxylate Interactionsmentioning

confidence: 99%

Experimental and Computational Evaluation of Heavy Metal Cation Adsorption for Molecular Design of Hydrothermal Char

et al. 2020

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A model hydrochar was synthesized from glucose at 180 °C and its Cu(II) sorption capacity was studied experimentally and computationally as an example of molecular-level adsorbent design. The sorption capacity of the glucose hydrochar was less than detection limits (3 mg g−1) and increased significantly with simple alkali treatments with hydroxide and carbonate salts of K and Na. Sorption capacity depended on the salt used for alkali treatment, with hydroxides leading to greater improvement than carbonates and K+ more than Na+. Subsequent zeta potential and infrared spectroscopy analysis implicated the importance of electrostatic interactions in Cu(II) sorption to the hydrochar surface. Computational modeling using Density Functional Theory (DFT) rationalized the binding as electrostatic interactions with carboxylate groups; similarly, DFT calculations were consistent with the finding that K+ was more effective than Na+ at activating the hydrochar. Based on this finding, custom-synthesized hydrochars were synthesized from glucose-acrylic acid and glucose-vinyl sulfonic acid precursors, with subsequent improvements in Cu(II) adsorption capacity. The performance of these hydrochars was compared with ion exchange resins, with the finding that Cu(II)-binding site stoichiometry is superior in the hydrochars compared with the resins, offering potential for future improvements in hydrochar design.

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“…The experiments were conducted in triplicate to increase the precision and minimise error. Removal percentage was calculated using Equation (1) [39]:…”

Section: Batch Biosorption Experimentsmentioning

confidence: 99%

Optimisation and Modelling of Pb(II) and Cu(II) Biosorption onto Red Algae (Gracilaria changii) by Using Response Surface Methodology

Isam

Baloo

Kutty

et al. 2019

Water

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The removal of Pb (II) and Cu (II) ions by using marine red macroalgae (Gracilaria changii) as a biosorbent material was evaluated through the batch equilibrium technique. The effect of solution pH on the removal of metal ions was investigated within the range of 2–7. The response surface methodology (RSM) technique involving central composite design (CCD) was utilised to optimise the three main sorption parameters, namely initial metal ion concentration, contact time, and biosorbent dosage, to achieve maximum ion removal. The models’ adequacy of response was verified by ANOVA. The optimum conditions for removal of Pb (II) and Cu (II) were as follows: pH values of 4.5 and 5, initial concentrations of 40 mg/L, contact times of 115 and 45 min, and biosorbent dosage of 1 g/L, at which the maximum removal percentages were 96.3% and 44.77%, respectively. The results of the adsorption isotherm study showed that the data fitted well with the Langmuir’s model for Pb (II) and Cu (II). The results of the adsorption kinetic study showed that the data fitted well with the pseudo-second order model for Pb (II) and Cu (II). In conclusion, red alga biomass exhibits great potential as an efficient low-cost sorbent for removal of metal ions.

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Enhanced adsorption of Pb(II) onto modified hydrochar: Modeling and mechanism analysis

Cited by 147 publications

References 37 publications

Removal of Aquatic Cadmium Ions Using Thiourea Modified Poplar Biochar

Removal of Aquatic Cadmium Ions Using Thiourea Modified Poplar Biochar

Experimental and Computational Evaluation of Heavy Metal Cation Adsorption for Molecular Design of Hydrothermal Char

Optimisation and Modelling of Pb(II) and Cu(II) Biosorption onto Red Algae (Gracilaria changii) by Using Response Surface Methodology

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