Modification of sludge-based biochar and its application to phosphorus adsorption from aqueous solution

Li, Zhiwei; Liu, Xuejiao; Wang, Yin

doi:10.1007/s10163-019-00921-6

Cited by 30 publications

(7 citation statements)

References 42 publications

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“…It is worth noting that S reflects the degree of order or disorder of the adsorbent surface during the adsorption of dye molecules. In particular, a positive value of S indicates an increase in the degree of disorder of the adsorption system [ 35 ].…”

Section: Methodsmentioning

confidence: 99%

Adsorption of Congo Red and Methylene Blue onto Nanopore-Structured Ashitaba Waste and Walnut Shell-Based Activated Carbons: Statistical Thermodynamic Investigations, Pore Size and Site Energy Distribution Studies

et al. 2022

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In this paper, an advanced statistical physics adsorption model (double-layer model with two energies) is successfully established. On the basis of this model, statistical thermodynamic functions (e.g., entropy (S), Gibbs free enthalpy (G), and internal energy (Eint)), pore size distribution (PSD), and site energy distribution (SED) functions were successfully developed and applied to investigate the adsorption mechanisms of nanopore-structured ashitaba waste-based activated carbons (AWAC) and walnut shell-based activated carbons (WSAC) on Congo red (CR) and methylene blue (MB) dyes in aqueous solutions. Statistical thermodynamic results indicated that the adsorption reactions involved in this study are entropy-increasing, endothermic, and spontaneous in nature. Furthermore, PSD and SED described the heterogeneity of these adsorbents in terms of geometry or structure and energy and illustrated that the aforementioned adsorption processes are endothermic physisorption. All in all, this study contributed to broadening the understanding of the adsorption mechanisms of dye molecules onto biomass-based activated carbons.

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Section: Methodsmentioning

confidence: 99%

Adsorption of Congo Red and Methylene Blue onto Nanopore-Structured Ashitaba Waste and Walnut Shell-Based Activated Carbons: Statistical Thermodynamic Investigations, Pore Size and Site Energy Distribution Studies

et al. 2022

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“…This indicated that the adsorption of TC onto S500 was mainly multi-molecule heterogeneous adsorption (Ma et al 2020), which may be related to coexisting adsorption mechanisms including the π-π interaction between S500 and TC (Chen et al 2007;Chen et al 2021). Furthermore, the value of 1/n was greater than 1, expounding the competition between adsorption sites increased with the equilibrium concentration increasing (Li et al 2020). However, the TC adsorption onto pyrolysis product pretreated through the activation of KOH could be greatly described by the Langmuir model (Fig.…”

Section: Adsorption Isothermsmentioning

confidence: 95%

Pyrolysis of municipal sludge without gas protection and its adsorption performance toward tetracycline: Effect of pyrolysis temperature and KOH activation

Chen

et al. 2022

Preprint

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Large amount of municipal sludge is difficulty to handle, its resource utilization is an effective measure. In this study, the municipal sludge from sewage treatment plant was pyrolyzed without nitrogen protection at different temperatures and KOH concentrations for activation. The pyrolysis products with higher surface aera and enriched pore structures could be obtained at the pyrolysis temperature of 500 ℃, and KOH activation could further increase the surface aera of the products. The maximum specific surface area was 44.71 m2/g, which was obtained under 2 mol/L KOH activation before pyrolysis at 500 ℃. And in this situation, the obtained pyrolysis products showed the maximum adsorption capacity of 50.75 mg/g toward tetracycline (TC). Moreover, the TC adsorption onto various pyrolysis products followed the pseudo-second-order kinetic model. Adsorption thermodynamics analysis suggested the TC adsorption onto products obtained at pyrolysis temperature of 500 ℃ was mainly the multi-molecule heterogeneous adsorption, while the TC adsorption onto pyrolysis product pretreated through the activation of KOH followed the monomer adsorption mechanism. This different adsorption mechanism was largely related to the pore structure, polarity, and aromaticity etc. of the adsorbent.

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“…Biochar, a carbon-rich porous material, has aromatic hydrocarbon surfaces, high pH, great cation exchange capacity and nutrient retention capacity [ 8 ]. Biochar derived from sludge, owing to its characteristics, has the potential to remediate contaminated soil, improve soil productivity and mitigate climate change [ 9 , 10 ]. Simultaneously, it is a well-established fact that several heavy metals in sludge are accumulated in biochar through the pyrolysis process [ 11 ] and the environmental risk of HMs-enriched biochar has attracted much attention [ 12 ].…”

Section: Introductionmentioning

confidence: 99%

The Fate of Heavy Metals and Risk Assessment of Heavy Metal in Pyrolysis Coupling with Acid Washing Treatment for Sewage Sludge

Liu

et al. 2023

Toxics

Self Cite

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Pyrolysis is an emerging and effective means for sludge disposal. Biochar derived from sludge has broad application prospects, however, is limited by heavy metals. In this study, the fate of heavy metals (HMs) in pyrolysis coupling with acid washing treatment for sewage sludge was comprehensively investigated for the first time. Most of the HMs redistributed in the pyrolyzed residues (biochar) after pyrolysis, and the enrichment order of the HMs was: Zn > Cu > Ni > Cr. Compared with various washing agents, phosphoric acid presented a superior washing effect on most heavy metals (Cu, Zn, and Cr) in biochars derived at low pyrolysis temperature and Ni in biochars derived at high pyrolysis temperature. The optimal washing conditions for heavy metals (including Cu, Zn, Cr, and Ni) removal by H3PO4 were obtained by batch washing experiments and the response surface methodology (RSM). The total maximum HM removal efficiency was 95.05% under the optimal washing specifications by H3PO4 (acid concentration of 2.47 mol/L, L/S of 9.85 mL/g, and a washing temperature of 71.18 °C). Kinetic results indicated that the washing process of heavy metals in sludge and biochars was controlled by a mixture of diffusion and surface chemical reactions. After phosphoric acid washing, the leaching concentrations of HMs in the solid residue were further reduced compared with that of biochar, which were below the USEPA limit value (5 mg/L). The solid residue after pyrolysis coupling with acid washing resulted in a low environmental risk for resource utilization (the values of the potential ecological risk index were lower than 20). This work provides an environmentally friendly alternative of pyrolysis coupling with acid washing treatment for sewage sludge from the viewpoint of the utilization of solid waste.

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Modification of sludge-based biochar and its application to phosphorus adsorption from aqueous solution

Cited by 30 publications

References 42 publications

Adsorption of Congo Red and Methylene Blue onto Nanopore-Structured Ashitaba Waste and Walnut Shell-Based Activated Carbons: Statistical Thermodynamic Investigations, Pore Size and Site Energy Distribution Studies

Adsorption of Congo Red and Methylene Blue onto Nanopore-Structured Ashitaba Waste and Walnut Shell-Based Activated Carbons: Statistical Thermodynamic Investigations, Pore Size and Site Energy Distribution Studies

Pyrolysis of municipal sludge without gas protection and its adsorption performance toward tetracycline: Effect of pyrolysis temperature and KOH activation

The Fate of Heavy Metals and Risk Assessment of Heavy Metal in Pyrolysis Coupling with Acid Washing Treatment for Sewage Sludge

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