Desalination and Water Treatment
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2024
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IF 1
Jiaoxia Sun,Xiqin Ma,Xiang Li,Jianxin Fan,Qingkong Chen,Xuelian Liu,Jin Pan
In this study, a new cationic polyacrylamide (CPAM) with different cationic degree was developed for the 17β-estradiol (E2) environmental estrogen removal. This new flocculant (PAA) was copolymerized byacrylamide (AM) and acryloyloxyethyl dimethylbenzyl ammonium chloride (AOD- BAC) using ultrasonic-initiated polymerization technique. The structure, morphology and thermal decomposition property of the prepared copolymer were analyzed through instrumental analyses such as Fourier transform infrared spectroscopy (FT-IR), 1 H nuclear magnetic resonance spectroscopy ( 1 HNMR), scanning electron microscopy (SEM) and thermogravimetry/differential scanning calorimetry (TG/DSC). The results showed that PAA was successfully synthesized. Meanwhile, it was demonstrated that PAA had a rough surface area with many holes and a favorable thermal stability. The E2 flocculation results demonstrated that the optimal flocculation conditions was at a cationic degree of 40%, pH = 7, stirring speed of 120 rpm, stirring time of 10 min, sedimentation time of 30 min and E2 initial concentration of 0.6 mg/L. In this condition, an excellent E2 flocculation performance (E2 removal rate: 92.3%, floc size: 22.1 μm) was obtained for PAA-3. During the E2 flocculation process, the charge neutralization was the main effect in both neutral (pH = 7) and acidic (pH = 4) conditions, but the adsorption was the dominant effect in alkaline (pH = 10) condition.
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DOI
高影响因子
Desalination and Water Treatment
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2024
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IF 1
Yuanfu Ma,Chen Wang,Qing Feng
In this study, we aimed to magnetically separate phosphate from natural water and change its source-to-sink conversion to prevent eutrophication. To this end, a promising material in terms of phosphate removal efficiency and magnetic separability was developed. Nine types of magnetic composite P-removal agents were prepared by changing the types of metal salts (i.e., Zn 2+ , Cu 2+ , Mg 2+ , Al 3+ , Fe 3+ , Zr 4+ , Y 3+ , Ce 3+ , and La 3+ ), and the optimal agent was determined to be La 3+ /poly (acrylamide-co-acryloyloxyethyl thimethylammonium chloride)/Fe 3 O 4 [La 3+ /CPAM/Fe 3 O 4 ] based on phosphate removal efficiency. The optimal synthesis conditions, including reaction time (4 h), reaction temperature (65°C), and the content of metal salts (12.96 mmol), were determined. The synthesized material was characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and vibrating-sample magnetometry. The results showed that the material featured a core–shell structure and exhibited good magnetic response. The experimental results showed that the removal process was rapid and completed within 20 min. Moreover, the material could greatly reduce P concentration, with phosphate removal efficiency reaching 90.07%. This material could effectively separate phosphate under the action of an external magnetic field and change the source-to-sink conversion of P, thereby preventing the risk of eutrophication.
研究领域:
环境科学
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水处理技术
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材料科学
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化学工程
✓ 已验证
DOI
高影响因子
MINERALS ENGINEERING
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2025
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IF 5
Ting Xiao,Wenjie Zou,Congzhong Tian,Wentao Hu,Zhijun Zhang,Chengyan Xu,Fang Zhou
Green and efficient flocculants are crucial for the effective treatment and recycling of mine wastewater. Herein, the flocculation performance and mechanism of a novel amphoteric chitosan-based flocculant CMC-g-CPAM on kaolinite suspensions were investigated through settling tests, zeta potential measurements, floc size distribution, quartz crystal microbalance with dissipation (QCM-D) and atomic force microscopy (AFM) measurements. Settling tests results revealed that CMC-g-CPAM displayed exceptional flocculation performance, achieving a settling rate of 18.21 m/h for kaolinite at natural pH, higher than that of chitosan-grafted-cationic acrylamide Chi-g-CPAM (11.19 m/h). The in-situ adsorption layer of CMC-g-CPAM on silica and alumina surfaces was more rigid than that of Chi-g-CPAM. Subsequently, more kaolinite particles were flocculated by CMC-g-CPAM, and formed a denser floc layer. The adsorption amounts of CMC-g-CPAM and Chi-g-CPAM on silica surfaces were found to be greater than those observed on alumina surfaces at natural pH. This phenomenon was related to the different surface charges of silica and alumina, electrostatic interactions between the polymers and surfaces. From AFM measurements, an attraction between the CMC-g-CPAM functionalized probe and the functional substrate as they approached each other and a weak adhesion force among CMC-g-CPAM (0.31 nN over 50 nm) were observed. These indicated the presence of intermolecular interactions among CMC-g-CPAM, which contributed to the formation of compact flocs. In contrast, an obvious repulsion was detected when the Chi-g-CPAM functionalized probe approached the functional substrate, inhibited the entanglement of polymer chains. Meanwhile, the interactions between multiple molecules and the substrate displayed a large adhesion force (2.10 nN over 150 nm), attributed to the less rigid adsorption layer of Chi-g-CPAM. Our findings would provide new insights into the design of flocculants and effective wastewater treatment.
研究领域:
环境工程
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高分子科学
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胶体与界面科学
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矿物加工
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废水处理
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）