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A novel amino-functionalized hydrochar material (referred to NH 2 -HCs) was prepared and used as the soil amendment to immobilize multi-contaminated soils for the first time. The results showed that the application of NH 2 -HCs significantly improved (P < 0.05) soil properties (i.e., pH value, cation exchange capacity and organic content). By introduction of NH 2 -HCs, the contaminated soil showed the highest value of 96.2%, 52.2% and 15.5% reductions in Cu, Pb and Cd bioavailable concentrations and the leaching toxicity of Cu, Pb and Cd were remarkably reduced by 98.1%, 31.3% and 30.4%, respectively. Most of exchangeable Cu, Pb and Cd reduced were transformed into its less available forms of oxidizable and residual fractions. Potential ecological risk assessment indicated that the element Cd accounted for the most of total risks in NH 2 -HCs amended soils. The mechanism study indicated that surface complexation, chemical chelating and cation-pi interaction of NH 2 -HCs played a vital role in the immobilization of heavy metals. Pot experiments further verified that the application of NH 2 -HCs significantly improved plant growth and reduced metal accumulations. The present study offered a novel approach to prepare amino-functionalized hydrochars with great potential as the green and alternative amendments for efficiently immobilizing heavy metals in multi-contaminated soil., Competing Interests: Declaration of competing interest The authors declare no competing financial interest., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The hydrochars derived from swine manure were prepared by CaO assisted hydrothermal carbonization (HTC), and their properties were investigated for the first time. The results showed that the pH and yield of the hydrochar were largely increased by CaO addition. HTC of swine manure increased the phosphorus (P) content in the hydrochar, and appropriately 100% of P as apatite-P was enriched in the hydrochar by CaO assisted HTC. Additionally, the CaO addition during HTC improved the porosity of the hydrochar. The FTIR analysis revealed that substantial functional groups were present on the surface of the hydrochar, indicating the facilitated exchange between the hydrochar and hydrophilic soil when the hydrochar was used for soil amendment. This study demonstrated that CaO assisted HTC was a novel strategy to quickly convert swine manure to the promising soil amendment especially for acidic soils., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The combustion behavior of the hydrochar from co-hydrothermal carbonization (HTC) of corn stalk (CS) and swine manure (SM) was thermogravimetrically investigated. Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) were used for kinetic analysis, and the thermodynamic parameters were determined. Results showed that HTC decreased the combustion property and stability of SM, while co-HTC with CS significantly improved the combustion performance of the hydrochar including the increased ignition temperature and decreased burnout temperature. HTC of SM decreased the average activation energy (E a ) value from 140.40 and 137.31 KJ/mol to 124.40 and 120.17 KJ/mol by FWO and KAS, respectively, and increasing proportion of CS during co-HTC increased the E a value of the hydrochar to 141.53-171.23 and 138.35-169.66 KJ/mol, respectively. The thermodynamic parameters confirmed the enhanced combustion reactivity of the hydrochar from co-HTC of CS and SM. These findings demonstrated that co-HTC with CS benefited the hydrochar production from SM with improved combustion performance., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The heteroatoms (N and S) doped porous carbons (HAPCs) were prepared from sewage sludge by hydrothermal carbonization and chemical activation for the first time. The porous structures and surface properties of HAPCs were characterized by multiple techniques including SEM-EDS, TEM, BET, XRD, Raman spectroscopy and Boehm's titration. The resultant materials were showed to be naturally N and S dual-doped porous carbons (HAPCs), especially for HAPC HCl+HF obtained by HCl-HF-washing, which was typical 3D hierarchically porous structure with abundant mesopores as well as big pore diameter. Then the performance of HAPC HCl+HF on AO7 removal was determined through Response surface methodology. The results showed the adsorption behavior obeyed Langmuir isotherm model and the maximum adsorption capacity was up to 440.53 mg g -1 at 25 °C. Kinetics study revealed that the adsorption followed pseudo second-order kinetic and intra-particle diffusion was the main control step. The high removal rate of AO7 was ascribed to the unique properties of HAPC HCl+HF . The great V mes and big pore diameter facilitated the diffusion of AO7 into the intra surface of particle. Meanwhile, the basic groups and doping of N and S made HAPC HCl+HF surface had positive charges, then strong π-π stacking interaction and electrostatic attraction contributed to the highly effective adsorption. This study indicated hydrothermal carbonization coupled with chemical activation was a cost-effective approach to prepare efficient heteroatoms doped porous carbon from sewage sludge towards azo dye contaminated wastewater treatment., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

A highly graphitized and heteroatom doped porous carbon was prepared from fish waste in the present study. The morphology and chemical composition of the resultant porous carbon were characterized by SEM-EDS, TEM, BET, XRD and Raman measurement. The prepared porous carbon was employed as an adsorbent for acid orange 7, a typical azo dye, removal from aqueous solution. The results showed that the porous carbon had ultrahigh surface area of 2146 m(2)/g, a high degree of graphitization structure and naturally doped with nitrogen and phosphorous. The maximum adsorption capacity of acid orange 7 reached 285.71 mg/g due to unique property of the prepared porous carbon. In addition, acid orange 7 adsorption onto the porous carbon well followed pseudo-second-order kinetics model and acid orange 7 diffusion in micropores was the potential rate controlling step., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

The low-cost composite, nano-zerovalent iron (NZVI) contained in porous carbon (PC), was prepared using pinewood sawdust and ferric chloride as starting materials. The key point of this strategy was that the production of PC and the formation of NZVI were accomplished simultaneously through a simple process. The composite PC/NZVI was characterized by XRD, BET and the adsorption and simultaneous dechlorination of PCBs were efficiently demonstrated. The results showed the pinewood sawdust was activated by ferric chloride and the surface area and the pore volume of obtained composite were 423 m(2)/g and 0.23 cm(3)/g, respectively. The produced NZVI, around 27 nm in diameter, catalyzed the formation of substantial mesopores in the composite. PC/NZVI exhibited an efficient dechlorination of PCBs at room temperature, and the dechlorinated-products could be completely adsorbed onto the composite. Accordingly, it is believed that PC/NZVI developed in the present study is practically applicable for PCBs-contaminated water purification., (Copyright 2009 Elsevier Ltd. All rights reserved.)

The solid by-product from power plant fueled with municipal solid waste and coal was used as a raw material to synthesize zeolite by fusion-hydrothermal process in order to effectively use this type of waste material. The effects of treatment conditions, including NaOH/ash ratio, operating temperature and hydrothermal reaction time, were investigated, and the product was applied to simulated wastewater treatment. The optimal conditions for zeolite X synthesis were: NaOH/ash ratio=1.2:1, fusion temperature=550 degrees C, crystallization time=6-10 h and crystallization temperature=90 degrees C. In the synthesis process, it was found that zeolite X tended to transform into zeolite HS when NaOH/ash ratio was 1.8 or higher, crystallization time was 14-18 h, operating temperature was 130 degrees C or higher. The CEC value, BET surface area and pore volume for the synthesized product at optimal conditions were 250 cmol kg(-1), 249 m(2) g(-1) and 0.46 cm(3) g(-1) respectively, higher than coal fly ash based zeolite. Furthermore, when applied to Zn(2+) contaminated wastewater treatment, the synthesized product presented larger adsorption capacity and bond energy than coal fly ash based zeolite, and the adsorption isotherm data could be well described by Langmuir and Freundlich isotherm models. These results demonstrated that the special type of co-combustion ash from power plant is suitable for synthesizing high quality zeolite, and the products are suitable for heavy metal removal from wastewater.

Abstract: The feasibility of hydrothermal char (HTC), a byproduct from biomass hydrothermal liquefaction for bio-oil production, as raw material for preparation of porous carbons was investigated in the present study. The resultant HTC-derived porous carbons were characterized and utilized as adsorbents for copper (II) and phenol removal from aqueous solution. Compared with porous carbons using pyrolytic char as precursor, the HTC-derived porous carbons exhibited unique textural features, e.g., narrow pore size distribution, high surface area and large pore size. In addition, FT-IR analysis confirmed that substantial amount of ketene groups existed on the surface of the HTC-derived porous carbons. As the adsorbents, the copper (II) adsorption onto HTC-derived carbons was strongly affected by the pH value of the solution in comparison with phenol adsorption. The carbons derived from pinewood and rice husk HTC exhibited high adsorption capacity of 83.88 and 39.30mg/g for phenol and 25.18 and 22.62mg/g for copper (II), respectively. The adsorption data for copper (II) and phenol onto the carbon adsorbents could be well described by Langmuir and Freundlich models. In comparison with pinewood sawdust HTC-derived carbon, the adsorption onto rice husk HTC-derived carbon preferentially followed Freundlich model due to the presence of silica on the surface. [Copyright &y& Elsevier]