PROCEEDINGS OF THE COMBUSTION INSTITUTE
·
2020
·
IF 5.627
Chao Feng,Mingkai Cheng,Xiangpeng Gao,Yu Qiao,Minghou Xu
This contribution reports the occurrence forms and leachability of major inorganic elements and heavy metals in the solid residue from smouldering combustion of sewage sludge (SS). Under the experimental conditions (moisture content: 50 wt%; sand-to-SS (wet) mass ratio of 4:1; and Darcy air flux: 3.5 cm/s), self-sustaining is achieved, destructing ∼98% of carbon in the SS and yielding a solid ash residue rich in Si, Al, P, Fe, K and Ca. The results from BCR (European Community Bureau of Reference) sequential extraction suggest that, majority of Na, K, Al, and Fe in the smouldering residue are presented as stable residue form, while Mg and Ca exist predominantly as acid-soluble. P in the residue is contributed by both reducible and residue fractions. All the heavy metals (As, Cr, Cd, Pb, Ni and Cu) in the residue are dominated by residue form, except Zn, which exists mainly as acid-soluble and reducible forms. Leachability tests demonstrate that considerable amounts of Ca (15.23—18.82%), Mg (11.92—16.74%), and K (5.91—7.04%) are readily leached out from the smouldering residue under pH 4.2—12.0. The concentrations of all the heavy metals in leachate meet the relevant regulatory values as determined by Toxicity Characteristic Leaching Procedure (TCLP). The smouldering residue generated here has potential to recover nutrients and is safe to be disposed via landfilling, addressing the environmental concerns that hinder the further development of smouldering combustion as a SS treatment technology.
研究领域:
环境科学
·
化学
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DOI
高影响因子
FUEL
·
2025
·
IF 7.5
Hugang Li,Hongxu Chen,Yongfei Gao,Yuhong Qin,Shuai Niu,Hui Zhou,Yuanhui Zhang
Crystallization of vivianite-phosphorus is a promising method to recover phosphate as a vital resource from sewage sludge hydrothermal carbonization (HTC) products. This study reveals the in-situ recrystallization mechanism of vivianite-phosphorus (Fe 3 (PO 4 ) 2 ·8H 2 O) regulated by FeCl 3 -assisted HTC in depth. The key finding includes the decipherment that phosphorus is mainly enriched in hydrochar (72.7 ± 2.9 %wt ∼ 84.4 ± 3.31 %wt). Further identified by HRTEM and XRD, dominant phosphorus is profiled as vivianite (Fe 3 (PO 4 ) 2 ·8H 2 O) with very few calcium phosphate crystals (Ca 3 (PO 4 ) 2 ) formation in hydrochar at near-neutral condition. Under acidic conditions, HMF oxidation triggers reductive dissolution of surface-bound Fe(III)-phosphate complexes, releasing Fe 2+ , HPO 4 2− , and PO 4 3− . The anoxic, reducing conditions at circumneutral pH created by HTC, combining with favorable Fe: P ratio (1.72) and lower calcium concentration (532 mg L −1 ), comprehensively drives the crystallization of Fe 3 (PO 4 ) 2 ·8H 2 O. This demonstration-of-practice study provides deep insights into dual organic waste resource and energy valorization.
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DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2021
·
IF 10.588
Siqi Tong,Dan Chen,Ping Mao,Xinbai Jiang,Aiwu Sun,Zhixiang Xu,Xiaodong Liu,Jinyou Shen
A novel magnetic hydrochar synthesized from Fenton sludge (FS) and sewage sludge (SS) was employed in the anaerobic decolorization of acid orange 7 (AO7). The stable presence of Fe 3 O 4 in magnetic hydrochar was confirmed by physicochemical characterization. The degradation efficiency of AO7 in the anaerobic system with the addition of hydrochar prepared in an optimal proportion (SS:FS=1:3, named as HC-1:3) could reach 98.55%, which was 1.91 times higher than the control system. Particularly, superior electrical conductivity, electron transport system activity and azo reductase activity of the sludge in anaerobic system with HC-1:3 were achieved. The redox of Fe(Ⅲ)/Fe(Ⅱ) in anaerobic system was realized by dissimilatory iron-reducing bacteria enriched with HC-1:3. According to the six-cycle batch experiments and 120-day continuous-flow UASB experiments, the addition of HC-1:3 into the anaerobic system facilitated the diversity of microbiological community and increased the ecological stability of anaerobic system. The possible electron transfer mechanism involving in the magnetic hydrochar-based anaerobic system for AO7 removal was speculated preliminarily. The as-prepared magnetic hydrochar not only showed a promising future in anaerobic system for recalcitrant contaminants degradation, but also provided a new approach for the resource utilization of FS and SS.
研究领域:
环境科学
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废水处理
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材料科学
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生物技术
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DOI
PubMed
高影响因子
MOLECULES
·
2026
·Vol. 31
·期 16
·2753
·
IF 5.1
Weiwei Zhu,Yi Ren,Yaxin Xiao,Shaoyu Du,Xiaoli Xie,Kao Chen
Due to the fact that municipal sludge incineration generates a large amount of toxic sewage sludge ash (SSA), cement solidification is becoming an efficient harmless treatment method. However, the large amount of phosphorus in sludge ash can delay the setting time of cement pastes and lead to a decrease in its later strength. Moreover, as an important non-renewable resource, the recycling and utilization of phosphorus is also a current research hotspot. To this end, this paper proposes to remove phosphorus from incinerated sewage sludge ash (ISSA) by the acid washing process, and, in response to the problem of reduced volcanic ash activity in acid-washed sewage sludge ash (ASSA), calcium chloride (CaCl2) is added as an activator to explore the optimal process and hydration mechanism for enhancing ASSA activity. This study removed phosphorus from calcined SSA (800 °C, 2 h) via acid washing (0.3 mol/L H2SO4, L/S = 10:1, 2 h) to obtain ASSA, and used CaCl2as an activator to improve its pozzolanic activity. Different CaCl2dosages (1–3%) were tested for paste setting time, 3/7/28 d compressive strength, and characterized by hydration heat, XRD, SEM, etc. Experimental results indicated that the synergistic addition of 2 wt.% CaCl2and 20 wt.% ASSA shortened the initial and final setting times by 38% and 23% to 142 min and 289 min, respectively. Meanwhile, the compressive strength at 28 days was improved by 24%, with a final strength value of 42 MPa. Microanalysis revealed abundant Friedel’s salt formation and a denser structure (fine mesopores 60%, coarse mesopores 26%), confirming CaCl2effectively activates ASSA for cement admixture use.
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DOI
高影响因子
Journal of Cleaner Production
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2025
·
IF 10
Chenyu Wang,Han Zhou,Chaoyue Wu,Weibo Sun,Xiaohui Sun,Chao He
Hydrothermal carbonization combined with wet chemical methods for treating sewage sludge produce valuable hydrochar and phosphorus. However, further investigation is needed to optimize the balance among phosphorus recovery, heavy metal leaching, residual hydrochar utilization to enhance overall process benefits. In this study, acid leaching on hydrochar was conducted using HCl, H 2 SO 4 , citric acid at 0.1 – 1.0 M acid concentration for 10 – 1440 min, the liquid-to-solid ratio between 50 to 500 mL/g. Employing single-factor experiments, response surface methodology, various characterization techniques, the impacts of acid leaching on the leaching rates of phosphorus and heavy metals, along with residual rate and properties of the remaining hydrochar, were quantitatively assessed. The results indicate leaching parameters directly impact the phosphorus leaching rate. HCl and H 2 SO 4 achieve their corresponding maximum phosphorus leaching rate within 60 min at acid concentration 0.5 M, liquid-to-solid ratio 500 mL/g, while using citric acid requires 360 min. When H 2 SO 4 is used as the extractant, the corresponding maximum phosphorus leaching rate can be maintained within a wider leaching time and acid concentration range. A moderate acid concentration, prolonged leaching time, higher liquid-to-solid ratio lead to increased levels of heavy metal concomitant leaching. Compared to HCl and citric acid, using H 2 SO 4 as extractant results in lower heavy metal leaching and lower sensitivity to leaching parameters. The residual rates of hydrochar range from 59.3% to 77.3%, with H 2 SO 4 and HCl as extractant yielding higher residual rates than citric acid. The properties of the remaining hydrochar were altered by acid leaching, resulting in a decrease in specific surface area and pore number, but an increase in oxygen-containing functional groups and calorific value, which affects its subsequent utilization. Finally, based on the aforementioned results and potential process scenarios, the selection of optimal acid leaching parameters was discussed. The results provide reference for the selection of phosphorus recovery and resource utilization pathway based on sludge-derived hydrochar.
研究领域:
环境科学
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资源与能源工程
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DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2025
·
IF 9
Min Sun,Ren-Ying Xiong,Jia-Ying Zhang,Lin-Feng Zhai,Ning Li
Nanoplastics (NPs) pose severe environmental threats, while sewage sludge management remains a major hurdle for municipal wastewater treatment plants (WWTPs). This study addresses these critical concerns by developing a ZnAl-layered double oxides@biochar (ZnAl-LDO@biochar) composite from sewage sludge for effective NPs remediation. Such material demonstrated remarkable adsorption capacities for five representative NPs, achieving 716.3 mg g −1 for polyethylene terephthalate (PET), 615.8 mg g −1 for polystyrene (PS), 406.0 mg g −1 for polymethyl methacrylate (PMMA), 271.6 mg g −1 for polyvinyl chloride (PVC), and 178.6 mg g −1 for polylactic acid (PLA) at 25 °C. During the adsorption process, LDO in ZnAl-LDO@biochar regenerated a layered double hydroxide (LDH) structure via the “memory effect”, enabling NPs adsorption via electrostatic attraction, hydrogen bonding and π-π interactions. Biochar contributed to hydrogen bonding and π-π interactions, meanwhile its dispersive effect promoting the exposure of LDH’s adsorption sites. A quantitative structure–activity relationship (QSAR) model was established by correlating the adsorption behavior with molecular descriptors of NPs. Guided by the QSAR model, ZnAl-LDO@biochar achieved a treatment capacity of 5 m 3 g −1 for removing high-concentration PET NPs from a WWTP effluent. These findings highlighted the exceptional potential of the ZnAl-LDO@biochar composite for real-world NPs remediation in water treatment.
研究领域:
环境科学
·
材料科学
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DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2024
·
IF 7.4
Shuai Guo,Jiyou Mu,Long Gao,Liya Ge,Grzegorz Lisak
This study presents a sustainable waste management method through co-hydrothermal carbonization (Co-HTC) of undehydrated sewage sludge (SS) and fungus bran (FB), effectively eliminating the need for additional water. The effects of the reaction severity factor (SF: 0.1, 0.2, and 0.3), the FB mixed ratio (FBMR: 0 %, 10 %, and 20 %), and the proportion of citric acid promoting agent (CAPA: 0 %, 10 %, and 20 %) on HTC performance were systematically investigated. The process was optimized for maximum energy yield (EY) using response surface methodology (RSM). The properties of the produced hydrochar, along with its EY and environmental impact, were thoroughly assessed. Results demonstrated that under optimal conditions (SF: 0.1, FBMR: 20 %, and CAPA: 20 %), EY increased by 45.84 % compared to hydrochar derived from dried SS. The dehydration and decarboxylation processes led to lower H/C and O/C ratios, producing hydrochar with reduced sulfur and nitrogen content, while the contents of alkali and alkaline earth metals, particularly calcium, increased. Furthermore, the optimized Co-HTC process had minimal environmental impact. In contrast to traditional HTC, which requires significant freshwater and involves high costs for SS drying, our innovative approach using undehydrated SS offers a cost-effective and environmentally friendly solution, paving the way for industrial-scale Co-HTC and sustainable waste valorization.
研究领域:
环境科学
·
能源工程
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产品关联
DOI
高影响因子
ENERGY & FUELS
·
2024
·
IF 5.2
Fanhui Liao,Yanchang Chu,Donghai Xu,Le Yang
Co/CeO2 catalysts with different morphologies of polyhedrons (Co/CeO2–P), rods (Co/CeO2–R), sheets (Co/CeO2–S) and cubes (Co/CeO2–C) were prepared and compared on the catalytic upgrading of hydrothermal liquefied (HTL) biocrude derived from municipal sewage sludge (MSS) to biofuel. The best quality biofuel was achieved on Co/CeO2–C with a higher heating value (HHV) of 39.10 MJ/kg, where the sulfur and oxygen contents were reduced to 0.007 and 9.19 wt %, while the carbon and hydrogen contents were elevated to 77.5 and 10.1 wt %, respectively. In contrast, the pure ceria support presented a slight improvement for the upgrading of biocrude. Overall, this work provides a feasible solution for high-value utilization of MSS to produce high-grade biofuel.
研究领域:
环境科学
·
化学工程
·
能源技术
·
催化
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产品关联
DOI
高影响因子
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
·
2025
·
IF 7.8
Wei Zou,Liming Liu,Xiaoping Liu,Hongxia Wang,Luna Zhao,Changlan Hou,Cheng Huang,Yin Zhou,Zhexian Wang,Yunbo Zhai
Heavy metals (HMs), as non-degradable hazardous substances, will continue to be enriched with the treatment of sewage sludge (SS), causing adverse effects on SS disposal and resource utilization. A green and accessible deep eutectic solvent (DES) based on choline chloride (ChCl) and lactic acid (La) was proposed to extract HMs from SS. The results showed that 80.7 % of Cd, 76.7 % of Zn, 56.9 % of Pb, and 30.9∼45.4 % of As, Cu, and Cr were removed from SS. In addition, DES exhibited a strong ability to destroy and dissolve organic matter like humic substances and extracted 66.6 % of the phosphorus. The treated sludge is more suitable for incineration with an increase of higher heating value and a decrease in ash content. Furthermore, the recyclability of DES was tested. After four recycles of DES, the accumulation of HMs and phosphorus (4.3 g/L) in DES provided potential benefits to recycle phosphorus. Thus, a hydrothermal method was conducted and successfully recycled about 70 % of phosphorus from DES. This research innovatively introduces DES to extract HMs from SS and realize phosphorus recovery, providing new ideas for SS harmlessness and valorization.
研究领域:
环境科学
·
废弃物处理
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DOI
高影响因子
Nanomaterials
·
2019
·Vol. 9
·期 2
·265
·
IF 4.034
Yi Wang,Weinan Zhao,Wanlan Zheng,Shuang Chen,Jinsheng Zhao
Porous activated carbon with specific morphology and structure are of particular importance for waste water treatment, especially for the adsorption of toxic hexavalent chromium Cr(VI). However, the scalable and cheap production of such absorbents still suffer a grand challenge. Herein, a new type of N-doped nanosheet was innovatively prepared from easily available and low-cost sewage sludge via a facile and recyclable KOH activation method. The N-doped porous carbon nanosheets (N-SAC) produced by introduction of KOH and dicyandiamide, which performed favourable features for metal ions adsorption (93.2% for Cr(VI)) due to its high specific surface area, tuneable pore size distributions and good hydrophilicity. Additionally, the capacity also remained high after two cycles of adsorption by thermal regeneration, with 90.8% removal rate. The DFT calculation also approved that the doping of N could optimize the Mulliken charges distribution and improve the HOMO energy and improve the adsorption ability of N-SAC. This original proposal may inspire new possibility of creating porous carbon absorbents in a recyclable method.
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DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2023
·
IF 7.7
Chenyu Wang,Biao Gui,Chaoyue Wu,Chao He,Lucheng Li,Xiaolong Ling,Xiaojun Zuo
Hydrothermal carbonization (HTC) is a promising technology for sewage sludge (SSL) utilization. However, the yield and performance of hydrochar need to be further improved produced when SSL is used as a feedstock must be improved further. Herein, a process combining physicochemical pretreatment , namely, Fenton oxidation (FO) and HTC was developed for SSL utilization. Moderate oxidation was found to improve the yield and performance of the produced hydrochar. The product distribution, yield, and properties of the hydrochar produced using the proposed combined process were compared with those of the hydrochar produced via direct HTC treatment. The pretreatment affected the surface structure and organic composition of SSL and promoted the carbonization of the intermediate products. Thus, compared with the yield of hydrochar (50.7 %) obtained via the direct HTC treatment, the yield of the hydrochar obtained using the combined process increased to 55.0–65.2 % (depending on the pretreatment condition). Hydrochar properties were enhanced using the combined process, and the energy density of hydrochar slightly decreased after pretreatment (1.2–13.1 %); however, the energy yields increased by 0.6–30.1 % due to the enhanced hydrochar yield. The carbonization degree of hydrochar improved, the carbon in the feedstock distributed to the hydrochar increased from 33.40 % to 46.09 %. Moreover, the hydrochar showed more distinct pore channels, slightly improving its combustion activity. This study shows the efficacy of the combined pretreatment–HTC process and provides an experimental basis for the combined hydrothermal treatment of SSL.
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DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2019
·
IF 7.65
Yaoping Hu,Zhijin Gao
Million tons of sewage sludge produced yearly creates a severe pollution problem to environment, and thus needs either to be properly disposed of, or recovered. Here, we demonstrate a value-added utilization of sewage sludge by converting its contained organics into nanosized carbon dots (CDs) with microwave irradiation. This synthetic method, using waste resources as precursors and avoiding the requirement of hazardous reagents and complex procedures, has the great advantage of low cost, environmental friendliness, and easy scalability. The resultant CDs exhibit excellent fluorescence properties with a large quantum yield (QY) of up to 21.7%, higher than the most values of waste-derived CDs. It is found that CDs can serve as a sensitive and selective sensor to detect para-Nitrophenol (p-NP), a toxic pollutant, through fluorescence quenching, giving a linear detection range of 0.2–20 μM and a detection limit of as low as 0.069 μM. Systematic investigations suggest that the inner filter effect (IFE) is the dominant sensing mechanism. Moreover, the practical applications of CDs for p-NP assay in real water samples achieve good results.
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DOI
PubMed
高影响因子
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