JOURNAL OF MEMBRANE SCIENCE
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2022
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IF 10.53
Ruonan Zhang,Yanchao Xu,Liguo Shen,Renjie Li,Hongjun Lin
Efficient separation of oil-in-water emulsion remains a decisive step for success of oily wastewater treatment . To achieve this goal, a novel strategy regarding combining membrane separation with in situ electrocoagulation based on sacrificial anodes and cathodic hydrogen evolution via conductive metalized fabric membrane was proposed. As a key component of this novel coupling system, nickel functionalized fabric membrane with high hydrophilicity and electrical conductivity (electrical resistance of ∼2 Ω cm −1 ) was successfully prepared via a low-cost and facile route, including steps of PVA (polyvinyl alcohol)/Ni coating and autocatalytic electroless Ni plating. The optimized conductive membranes exhibited high permeate flux (19.3 × 10 5 L m −2 h −1 ·bar −1 ), separation efficiencies (99.5%), and separation stability to separate oil/water mixtures during the gravity-driven filtration process. To achieve the ideal performance to separate oil-in-water emulsion, a coupled electrocoagulation-membrane separation system was constructed with Ni@PVA membrane and Al mesh as the cathode and anode, respectively. It was shown that the coupled electrocoagulation-membrane separation system could achieve 99.4% rejection with high flux of 12.0 × 10 3 L m −2 h −1 ·bar −1 for oil/water emulsion separation, under the current density of 8 mA cm −2 and 20 min electrolysis time. This study revealed that the proposed electrocoagulation-membrane separation system based on Ni@PVA membrane is a promising technique in oil/water separation.
研究领域:
环境科学
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材料科学
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DOI
高影响因子
Journal of Environmental Chemical Engineering
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2022
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IF 7.968
Yutong Han,Jingjing Zheng,Chao Jiang,Fan Zhang,Lecheng Wei,Liang Zhu
The unceasing algae blooms have led to the deterioration of water quality and ecological imbalance in the entire globe, it’s urgent to investigate its treatment and resource utilization technology . In this study, treated algae was prepared to produce the biochar and then it was utilized as a coagulant for the removal of Microcystis aeruginosa . To improve the pore structure of algae-derived biochar for improving the removal capacity of M. aeruginosa , hydrochloric acid (HCl) modification was applied and optimized by Box-Behnken model-based response surface methodology . After modification by HCl, the specific surface area, pore volume, and average pore diameter of modified algae-derived biochar (MAB) increased to 38.34 m 2 /g, 0.073 cm³ /g, and 7.42 nm, respectively. The removal efficiency of Microcystis aeruginosa (The initial cell density: 4 ×10 6 cells/mL) by the MAB reached 99.02% ± 0.18 under the optimum condition obtained with response surface experiment (dosage of 287.46 mg/L, pH of 8.2, stirring rate of 175 rpm, and stirring time of 6.4 min). At the same time, the removal efficiencies of Chl a, turbidity and total phosphorus of polluted waters reached more than 84%, 91% and 60%, respectively. The dissolved organic matters were removed synchronously, thereby reducing the disinfection by-products formation potential. Electrostatic adsorption has been determined as the predominant force during the coagulation process. In conclusion, the HCl has been proved to be an effective strategy to improve the pore structure and algal removal capacity of MAB, and the MAB could be applied as the suitable materials for the algal coagulation with the advantage of resource utilization.
研究领域:
环境科学
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水处理
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生物技术
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DOI
高影响因子
APPLIED THERMAL ENGINEERING
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2022
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IF 6.465
Feifan Huang,Weijun Liu,Shaoai Chen,Zhongxun Tian,Jingtao Wei
Thermal desorption of adsorbate in activated carbon is the main part in the thermal regeneration process of spent activated carbon, and previous studies have carried out a series of numerical simulations on it. However, since activated carbon is a porous medium, the heat and mass transfer in activated carbon is different from that in solid. In this paper, a multiphase model of heat and mass transfer in porous media was constructed to study the thermal desorption characteristics of adsorbate in spent activated carbon. In addition, a simplified evaporation rate formula is proposed in this paper, and the agreement between the simulation and the experimental results is verified. When the surroundingtemperature is less than 673.15 K, increasing the surrounding temperature has a significant effect on reducing the thermal desorption time of the adsorbate. Using activated carbon with a thermal conductivity of 5 W / m ∙ K can save about 40% of energy consumption. The model established in this paper can accurately simulate the thermal desorption of adsorbate in activated carbon, which is helpful to deeply understand the mechanism of activated carbon thermal regeneration. In engineering practice, the model can provide technical support for optimizing the thermal regeneration process of spent activated carbon and reducing energy consumption in a targeted manner.
研究领域:
环境科学
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化学工程
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2022
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IF 16.744
Xin Mao,Jing Shen,Yu Shen,Wenxin Shi,Bing Zhang
This study proposed and applied an innovative heat/powdered activated carbon (PAC)/persulfate (PS) pre-treatment system for the first time in an aerobic granular sludge–membrane system (AGSMS). We examined the effects of the heat/PAC/PS system on membrane fouling mitigation and contaminant removal and qualitatively evaluated the contribution of adsorption and oxidation to membrane fouling control. Compared to other pre-treatment systems, the heat/PAC/PS system could enhance the removal of pollutants, reduce fouling resistance, and delay the decline of permeation flux, resulting in low foulant content on the membrane surface and formation of a loose and porous cake layer. According to radical scavenging experiments, the excellent heat/PAC/PS system pre-treatment performance was attributed to the PAC adsorption capacity and non-radical oxidation pathway. Thermal synergy played a significant role in promoting adsorption and oxidation abilities. The extended Derjaguin–Landau–Verwey–Overbeek theory indicated that the high-energy barrier in the heat/PAC/PS system was an important factor in inhibiting the adhesion of foulants to the membrane surface. Furthermore, the correlation analysis suggested that membrane fouling control should focus on the removal of chemical oxygen demand and suspended solids. This study provides a new approach for membrane fouling mitigation through AGSMS in municipal wastewater treatment.
研究领域:
环境科学
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水处理工程
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产品关联
DOI
高影响因子
Journal of Water Process Engineering
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2022
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IF 7.34
Yanting Qin,Hui Jia,Weixuan Liu,Na Lu,Huu Hao Ngo,Jie Wang
A low-cost in-situ micro laser transmission (IMLT) analysis system for particle size monitoring based on the principle of laser transmission extinction was developed to monitor the flocculation process . In this study, the IMLT system was used to obtain the voltage generated with the changes of flocculant dosage and floc sizes in different flocculation stages. A typical machine learning model, convolution neural network (CNN) method was built to manage the flocculant dosage, detection voltage and floc size to improve the accuracy of the correlation between the them. Results of IMLT revealed that the particle size of flocs was inversely proportional to the voltage, and a larger final voltage R value indicated better effects of flocculation and sedimentation. The correlation between the particle size obtained by CNN training and measured particle size was 42.4 % and 30.5 % higher than that without training at low and high concentrations, respectively. IMLT is effective in reflecting the floc sedimentation, stability and dynamic influence of the coagulant aid on flocculation system.
研究领域:
环境科学
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水处理工程
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机器学习应用
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DOI
高影响因子
PLoS One
·
2021
·Vol. 16
·期 3
·e0247948
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IF 3.24
Shiliang Xu,Mengke Cui,Renjie Chen,Qiaoqing Qiu,Jiacai Xie,Yuxin Fan,Xiaohu Dai,Bin Dong
With the increasing demand for energy, fracturing technology is widely used in oilfield operations over the last decades. Typically, fracturing fluids contain various additives such as cross linkers, thickeners and proppants, and so forth, which makes it possess the properties of considerably complicated components and difficult processing procedure. There are still some difficult points needing to be explored and resolved in the hydroxypropyl guar gum (HPG) removal process, e.g., high viscosity and removal of macromolecular organic compounds. Our works provided a facile and economical HPG removal technology for fracturing fluids by designing a series of processes including gel-breaking, coagulation and precipitation according to the diffusion double layer theory. After this treatment process, the fracturing fluid can meet the requirements of reinjection, and the whole process was environment friendly without secondary pollution characteristics. In this work, the fracturing fluid were characterized by scanning electron microscopy (SEM), Energy dispersive X-ray (EDX), X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) spectroscopy technologies, etc. Further, the micro-stabilization and destabilization mechanisms of HPG in fracturing fluid were carefully investigated. This study maybe opens up new perspective for HPG removal technologies, exhibiting a low cost and strong applicability in both fundamental research and practical applications.
研究领域:
石油工程
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环境科学
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材料科学
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DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
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2022
·Vol. 30
·期 7
·18285-18295
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IF 5.19
Xu Xia,Guo Jun,Yang Ruoying,Gao Yu,Xue Yingang,Wang Liping,Zhang Ling,Zhang Qiuya,Peng Mingguo,Liu Xuefeng
Titanium xerogel coagulant (TXC) is a new type of coagulant that has attracted much attention in recent years. However, the tetracycline removal performance of TXC was not satisfactory because low isoelectric point (pH iep ) inhibited the electrical neutralization efficiency of TXC in an alkaline environment. To overcome this shortcoming, a composite xerogel coagulant (titanium-aluminum xerogel composite coagulant) was prepared. The removal of tetracycline and turbidity was used as evaluation indexes. It was proved that the combination of aluminum (III) and titanium (IV) enhanced the resistance of TXC to pH. The synthesized titanium-aluminum xerogel composite coagulant (TXAC) has an excellent removal ability of tetracycline in a wide pH range (pH = 5–10). At pH 8.8, the dosage required to remove 80% tetracycline from water decreased from 93 (TXC) to 35 mg/L (TXAC). The reason for this improvement could be attributed to (i) aluminum (III) enhanced the electric neutralization of TXC to negatively charged pollutants in an alkaline environment; (ii) the complexing ability of organic matter and aluminum (III) was enhanced. This work provides a feasible scheme for the pretreatment of tetracycline in water to meet the pretreatment requirements of special water.
研究领域:
环境科学
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水处理技术
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产品关联
DOI
PubMed
高影响因子
Environmental Earth Sciences
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2023
·Vol. 82
·期 2
·1-15
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IF 2.8
Guo Dongdong,Wan Yong,Li Jiangshan,Liu Ruiqi,Liu Lei,Xue Qiang
Modified bentonites for the anti-seepage system have been attracting global attention. At the same time, the performances of modified bentonite containing retardation barrier exposed to organic–heavy metal pollutants have not been fully reported. In this study, the adsorption performances (one of the key evaluation indicators of retardation barrier) of nine kinds of commonly used modified bentonites on multiple contaminants were comparatively investigated. The x-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analyses were also performed to unravel the adsorption mechanisms. Results show that the adsorption of modified bentonites on phenol and Pb(II) follows the order of SB-16 > PVA > CTAB > APAM > CTAB + PAC > PAC > CPAM > CTAB + PAC > CTAB + CPAM + APAM. Among all the samples, the bentonite modified with SB-16 showed the highest adsorption capacities for phenol and Pb(II). The surfactant molecules inserted in the interlayer space of montmorillonite increase the substrate spacing, which changes the structural properties of the bentonite from hydrophilic to hydrophobic and increases the adsorption of organic contaminants. On the other hand, the polymer has functional groups such as hydroxyl and carboxyl that can form a spatial three-dimensional cross-linking structure on the bentonite surface, providing more adsorption sites for heavy metal ions. These findings indicate the potential industrial applications of modified bentonite in a contaminant barrier system.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2023
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IF 15.1
Wei Wu,Xuesong Li,Bo Zhou,Zhiwei Wang
While chemical conditioning is the most commonly used conditioning process for sludge dewatering, the dewaterability of chemically conditioned sludge is found to be significantly affected by shear force. However, relevant studies are still lacked, which obstructed an in-depth understanding on sludge conditioning. In this study, we systematically investigated the impacts of floc breakage induced by shearing on the sludges conditioned with polyacrylamides (PAMs)/inorganic salts. Although PAM-conditioned sludges had better structural strength and dewaterability than the ones conditioned with inorganic salts, they exhibited a drastically deteriorated dewaterability upon floc breakage after shearing. Further analysis revealed that the PAM-conditioned flocs were mainly wrapped by polymer chains and thus floc breakage would lead to a substantial release of extracellular polymeric substance (EPS) and exposure of massive non-neutralized negative charge. In comparison, the coagulation by inorganic salts was mainly completed by charge neutralization and compression of EPS, which resulted in a conditioned sludge with a much less deteriorated dewaterability after shearing. Accordingly, PAMs are suggested as the chemical agents if screw pump is used for the sludge conditioning, while extra shearing should be minimized in the conditioning process. Inorganic salts are more applicable for the conditioning layout with a flexibly located equalization tank due to their relatively low coagulation kinetics but well-maintained sludge dewaterability. This study fills some critical knowledge gaps in the fundamental understandings on chemical conditioning process and offers a guideline for the selection of practical conditioning strategy.
研究领域:
环境科学
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污水处理
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产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2023
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IF 8.6
Congzhong Shi,Qiming Wang,Daiqi Li,Beini Zeng,Qingtao Liu,Yongming Cui,Jinfeng Wang,Xungai Wang
Wool is perceived to be a clean and green natural fibre . However, raw wool contains substantial amounts of contaminants that must be removed in a wool scouring process before the wool can be used as a textile fibre . Coagulation is the first step for scouring wastewater treatment . But the role of inorganic coagulants in increasing sludge density for scouring wastewater treatment remains unclear. This work systematically prepared a series of inorganic composite coagulants (polyaluminium ferric silicate (PAFS)) and investigated their efficiency for treating wool scouring wastewater. Compared with conventional coagulants, polyaluminium chloride (PAC) and polyferric sulfate (PFS), PAFS showed improved coagulation performance over a wider pH range (3–7), achieving higher removal rates of 97 % and 99 % for chemical oxygen demand (COD) and turbidity, respectively. In addition, PAFS showed its advantages for practical wastewater treatment, including fast floc settling rate, increased sludge density (with a reduced sludge volume) and low floc moisture content. This optimized PAFS was successfully obtained in a scaled-up process. Zeta potential tests revealed that PAFS coagulated colloidal particles by the synergistic action of electro-neutralization and adsorption bridging. This work has practical implications for increasing the efficiency of wastewater treatment and reducing the environmental impact of wool scouring.
研究领域:
环境科学
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纺织工程
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化学工程
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产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
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2023
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IF 7.4
Xiaohui Sun,Ziyi Chen,Keyu Guo,Jianbo Fei,Zijun Dong,Hao Xiong
Geopolymeric flocculation-solidification of the tail slurry of shield tunnelling spoil after sand separation was investigated to replace the low-efficient flocculation and filter-pressing method currently adopted on site. The geopolymeric flocculation-solidification agent (GBFS-FS) consisting of flocculation component and geopolymeric solidification component (granulated blast-furnace slag (GBFS) activated by alkali) was prepared and investigated through flocculation-sedimentation test, dewatering model test, unconfined compression test, SEM test, etc. In the flocculation-sedimentation test, the GBFS-FS agent demonstrated the best flocculation effect as compared with other cementitious flocculation-solidification agents. The dewatering model tests revealed that adding the GBFS-FS agent into the slurry can not only dewater the slurry efficiently, but also generate solidified clayey sediments with quickly-increased strength. The solidified clayey sediments with GBFS-FS showed strengths 3.5 times higher than others with cementitious agents at a 28-day curing age. The GBFS-FS agent can also facilitate to make controlled low-strength material (CLSM) using the tail slurry. The fluidity and strength of CLSM with GBFS-FS were distinctly better than those of other groups. SEM test shows that the components of the GBFS-FS agent can interact to avoid large flocs and support each other in strength growth.
研究领域:
土木工程
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环境工程
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产品关联
DOI
高影响因子
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
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2023
·Vol. 148
·期 10
·4255-4266
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IF 4.4
Nie Hongqi,Yang Xu-Hao,Yang Su-Lan,Fershtat Leonid,Yan Qi-Long
The nano-sized metal oxides (MOs) as combustion catalysts have been widely employed in solid rocket propellants, but the functionality of these materials is greatly restricted owing to their agglomeration. The catalytic activity of MOs on nanoscale was found to be significantly improved by the incorporation of MOs with carbon nanomaterials, which normally act as carriers allowing for well-distribution of MOs. In this paper, the CuO and Fe 2 O 3 nanoparticles were produced by hydrothermal method and the CuO@C and Fe 2 O 3 @C nanocomposites with a uniform structure have been fabricated by an in-situ growth of corresponding MOs on the porous activated carbon (pAC). The morphology of the prepared MOs nanoparticles and resultant pAC carried ones were characterized using scanning electron microscope. It has been shown that the CuO and Fe 2 O 3 nanoparticles are tightly adhered and dispersed on the surface of pAC. Their catalytic effects on the thermal decomposition of hexogen (RDX) were analyzed using thermal analysis techniques. Results indicate that the thermal decomposition of RDX was considerably promoted in the presence of these catalysts, where the CuO@C and Fe 2 O 3 @C were found to be capable of lowering the T p for RDX by 14.8 °C and 12.4 °C, respectively. In addition, the decomposition kinetics of RDX in the presence of these catalysts have been evaluated with the DTG and DSC experimental data, and results show that the CuO@C and Fe 2 O 3 @C were able to reduce the E a of RDX decomposition by 39.8 kJ mol −1 and 50.7 kJ mol −1 , which is suggestive of an enhanced decomposition process for RDX by addition of carbon-loaded catalysts. The TG-FTIR analysis indicates that, in the presence of CuO@C and Fe 2 O 3 @C, the gaseous products are dominated by N 2 O in RDX decomposition.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）