JOURNAL OF HAZARDOUS MATERIALS
·
2015
·
IF 4.529
Lijuan Feng,Shuang Zhao,Shenglei Sun,Wenyu Wang,Baoyu Gao,Qinyan Yue
The influences of solution pH on coagulation/ultrafiltration (C–UF) process were investigated by using three purified Al species of polyaluminium chloride (PACl). A series of online-simulation experiments were developed to assess the coagulation removal efficiencies (turbidity, UV 254 ), floc properties and membrane fouling in this paper. The results showed that change of pH had a significant impact on coagulation efficiencies, floc properties, membrane flux as well as the whole process. Under acidic condition, the hydrolysis action of aluminum salts was restrained which is bad for charge neutralization. While under alkaline region, absorption was the dominant mechanism to combine HA–Kaolin. Meanwhile, HA is apt to soluble by deprotonating under alkaline region which is hard to remove. These common effects made the experiment results complex. HA removal efficiency of Al a and Al b were higher than that of Al c , but the turbidity removal by Al c was slightly higher under the same pH condition. Flocs generated by Al a at pH 6 had advantages such as larger size and the most loosely structure which contributed the most to alleviating membrane fouling. Membrane fouling with Al b and Al c in alkaline range was more serious than that in acidic range.
研究领域:
环境科学
·
水处理工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2021
·
IF 10.588
Tao Huang,Dongping Song,Lulu Zhou,Hui Tao,Aiyin Li,Shu-wen Zhang,Long-fei Liu
The natural ecosystem will continually deteriorate for decades by the leakage of Cs and Sr isotopes. The exploration of the new materials or techniques for the efficient treatment of radioactive wastewater is critically important. In this study, a dielectric barrier discharge (DBD) configuration was constructed to operate the non-thermal plasma (NTP). The NTP was incorporated into the synthesis of polyaluminum chloride (PAC) in two different procedures to intensify the synthesis of PAC (NTP-PAC) and enhance the further removal of Cs and Sr from wastewater. The employment of NTP in two procedures both had significantly changed the physicochemical characteristics of PAC materials, which facilitated the further adsorption application of NTP-PAC on the treatment of Cs + and Sr 2+ . Different molecular, morphological, and adsorption characteristics were confirmed to the NTP-PAC materials. The heterogeneous adsorption of the NTP-PAC can be appropriately fitted by both the pseudo-first-order kinetic model and the Elovich model. Both physisorption and chemisorption reaction mechanisms were ensured for the heterogeneous adsorption of the NTP-PAC material towards Cs + and Sr 2+ , which guaranteed the excellent adsorption performance of NTP-PAC materials compared to PAC. The electron collisions caused by NTP with alum pulp created highly reactive growth precursors and intensified the nucleation and hydrolysis polymerization of PAC. The employment of NTP explicitly broadens the reaction pathways between PAC and cationic contaminants in the aqueous environment, which expands the application area of PAC materials in environmental sustainability.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2016
·Vol. 24
·期 6
·5179-5188
·
IF 2.76
Sun Jianzhang,Gao Baoyu,Zhao Shuang,Li Ruihua,Yue Qinyan,Wang Yan,Liu Siqi
It is confirmed that nano-ZnO (nZnO) has impact on environment and is considered as heavy metal pollutants. It is a new technology that applies coagulation process to simultaneous removal of the nanoparticles and heavy metals. Environmental chemical behavior of ZnO in water, such as the dispersion, aggregation, sedimentation, and dissolution of releasing metal ions, has been systematically studied in this paper. The result shows that three kinds of nZnO state such as compacted sediment, suspended, and released is separately 36.54 %, 40.61 %, and 22.86 %. Enteromorpha polysaccharide (Ep) was used together with polyaluminum chloride (PAC) in surface water purification. In order to study the mechanism of simultaneous removal of residual nZnO particles and Zn 2+ , coagulation process was further applied in this study. The evolution of flocs size, strength, and recovery ability and fractal structure due to Ep addition was systematically studied in this paper. Results indicated that PAC-Ep was efficient in removing nZnO and Zn 2+ , which leads to more than 95 % particles, 50–60 % natural organic matter (NOM) removed, and 35 % of resolved heavy metal ion adsorbing-chelation. Ep was an efficient coagulant aid in enhancing performance of coagulation and generating flocs with bigger sizes, faster growth rates, and higher recovery abilities. Additionally, the flocs formed by PAC-Ep presented a much looser structure than flocs formed only by PAC.
ᅟ
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED SURFACE SCIENCE
·
2024
·
IF 6.3
Yijiang Li,Chen Chen,Wencheng Xia,Yujin Sun,Hongxin Qiu
In this study, in-situ flocculation kinetics tests, fourier transform infrared spectroscopy and DFT theoretical calculation were used to analyze flocs properties of calcite flocs under combination of sodium alginate and AlCl 3 /polyaluminum chloride (PAC) and their adsorption mechanism. The results showed that the average size of calcite flocs treated with AlCl 3 -sodium alginate was smaller than that of flocs treated with PAC-sodium alginate. The number of residual fine particles in the slurry treated with AlCl 3 -sodium alginate was more than that in the slurry treated with PAC-sodium alginate. However, the fractal dimension of calcite flocs treated with AlCl 3 -sodium alginate was larger than those treated with PAC-sodium alginate. The sodium alginate and Al 3+ could form chemical adsorption on the calcite surface. AlCl 3 has a higher content of Ala than PAC. Ala could form chemical adsorption between sodium alginate and calcite, resulting in a high strength and fractal dimension of calcite flocs. Alb and Alc was not easily able to form metal bridges between calcite and sodium alginate. The sweep effect of PAC and sodium alginate leads to the formation of large-sized flocs. This work can promote the supplication of sodium alginate as a green flocculant.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Frontiers of Environmental Science & Engineering
·
2018
·Vol. 12
·期 3
·1-8
·
IF 1.961
Sun Jianzhang,Gao Baoyu,Luo Yuanxia,Xue Moxi,Xu Xing,Yue Qinyan,Wang Yan
Enteromorpha polysaccharide (Ep) extracted from alga a novel green coagulant aid for nanoparticles (NPs) and heavy metal ions removal and the structure of EP was intensively studied in this study. The integration of Ep with polyaluminum chloride (PAC-Ep) coagulants exhibited higher coagulation performance than that of the polyaluminum chloride (PAC) because of the negatively charged NPs suspension and humic aid (HA) solution. Significant high removal efficiencies of dissolved organic matter (94.1%), turbidity (99.3%) and Zn ions (69.3%) were achieved by the PAC-Ep coagulants. The dual-coagulation properties of PAC-Ep for different pollutants was based on multiple mechanisms, including (i) Al 3+ charge neutralization; (ii) hydroxy aluminum hydroxyl bridging formed polynuclearhydroxy complexes bridge and sweep colloidal particles; (iii) adsorption and bridging of Ep chain for the NPs and heavy metal ions. Results indicated that the destabilization of colloid was induced by the coexisting HA and higher removal was achieved as ions adsorption was enhance in the presence of HA complexation. On the basis of that, the extraction of polysaccharide is a promising candidate for its high coagulation performance in water treatment.
研究领域:
环境科学
·
水处理技术
✓ 已验证
DOI
高影响因子
Journal of Environmental Sciences
·
2021
·
IF 5.565
Xueyi Dong,Xihua Cao,Wenbin Jiang,Xiuxian Song,Zhiming Yu,Shitao Yu
Polyaluminum chloride modified clay (PAC-MC) is a safe and efficient red tide control agent that has been studied and applied worldwide. Although it is well known that the distribution of hydrolytic aluminum species in PAC affects its flocculation , little is known about the influence of particulars aluminum species on the microalgae removal efficiency of PAC-MC; this lack of knowledge creates a bottleneck in the development of more efficient MCs based on aluminum salts. The ferron method was used in this study to quantitatively analyze the distributions of and variations in different hydrolytic aluminum species during the process of microalgae removal by PAC-MC. The results showed that Al a , which made up 5%–20% of the total aluminum, and Al p , which made up 15%–55% of the total aluminum, significantly affected microalgae removal, with Pearson's correlation coefficients of 0.83 and 0.89, respectively. Most of the aluminum in the PAC-MC sank rapidly into the sediments, but the rate and velocity of settlement were affected by the dose of modified clay. The optimal dose of PAC-MC for precipitating microalgae was determined based on its aluminum profile. These results provide guidance for the precise application of PAC-MC in the control of harmful algal blooms .
研究领域:
环境科学
·
水处理工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2019
·
IF 4.561
Shaoxiu Li,Zhijun Li,Bohan Ke,Zhifeng He,Yiyang Cui,Zhengyu Pan,Dongmei Li,Su Huang,Chan Lai,Jiongheng Su
Magnetic multi-walled carbon nanotubes (MWCNTs) prepared by chemical co-precipitation method were loaded with polyaluminium chloride (PAC) using microwave irradiation to synthesize magnetic PAC multi-walled carbon nanotubes (M-PAC-MWCNTs) for removal of humic acid (HA) from aqueous solution. M-PAC-MWCNTs were characterized by field emission scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR) spectroscopy, specific surface area (SSA) and vibrating-sample magnetometer (VSM), respectively. The results showed that PAC and magnetic matters Fe 3 O 4 and γ-Fe 2 O 3 were coated on MWCNTs. The effect of M-PAC-MWCNTs dosage, pH value, HA initial concentration and contact time on removing HA from aqueous solution was also investigated. The HA removal rate was high to 98.57% at M-PAC-MWCNTs dosage of 0.5 g·L −1 and pH 7 for reaction time of 30 min at HA concentration 20 mg·L −1 . In addition, kinetic, equilibrium and thermodynamic of the adsorption of HA on M-PAC-MWCNTs were studied. The adsorption process was well fitted by the pseudo-second-order kinetic model and Temkin isotherm model, declaring that chemical adsorption was primary and physical adsorption was complementary. Thermodynamics analysis revealed ΔG 0 < 0, ΔH 0 > 0 and ΔS 0 > 0, suggesting that the HA adsorption on M-PAC-MWCNTs was a spontaneous, endothermic in nature and entropy increase process. After MWCNTs were magnetized and modified by PAC, the adsorption performance of MWCNTs was greatly enhanced, mainly attributed to the interaction between PAC and humic acid through hydrogen-bond and electrostatic attraction.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
WATER AIR AND SOIL POLLUTION
·
2021
·Vol. 233
·期 1
·1-9
·
IF 2.52
Yu Hui-Bo,Zhang Xian-Qiu,Han Xue,Yang Zhen-Zhen,Zhou Ya-Wen,Ding Wen,Du Ming-Xia
It is reported that residual aluminum from coagulation pretreatment can increase membrane fouling in nanofiltration (NF) or reverse osmosis (RO) desalination systems. However, the membrane fouling mechanism of residual aluminum and the effective control measures are not very clear. In this study, the nanofiltration membrane fouling caused by poly-aluminum chloride (PACl), the inhibitory effect of amino trimethylene phosphonic acid (ATMP) on aluminum foulants, and calcium carbonate scale in the presence of residual aluminum were investigated by permeate experiments and scanning electron microscopy (SEM) observation of the fouled membranes. Besides, the effect of adding ultrafiltration before nanofiltration on reducing membrane fouling caused by residual aluminum was also investigated. The results showed that most of the residual aluminum in feed eventually formed insoluble particles and fine flocs, and accumulated gradually on the membrane surface, which was a typical colloid particle fouling. ATMP can reduce the membrane fouling caused by residual aluminum to some extent, and the permeate flux ratio ( J/J c ) increased from 0.83 to 0.89 when ATMP increased to the optimal dose of 6 mg⋅L −1 . However, this means can still effectively eliminate carbonate scale, even in the presence of residual aluminum. Moreover, ultrafiltration pretreatment prior to nanofiltration was very effective to control membrane fouling, and the comprehensive cost was calculated to be only 0.006 $⋅m −3 . Therefore, the combined process of coagulation-ultrafiltration as a pretreatment of nanofiltration or reverse osmosis should be an ideal way to prevent membrane fouling caused by residual aluminum.
研究领域:
环境科学
·
水处理工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMOSPHERE
·
2020
·
IF 5.778
Guocheng Zhu,Nana Xiong,Chuang Wang,Zhongwu Li,Andrew S. Hursthouse
Removing dissolved organic matter (DOM) with polyaluminium chloride is one of the primary goals of drinking water treatment . In this study, a new HMW framework was proposed, which divided the factors affecting coagulation into three parts consisting of hydraulic condition (H), metal salt (M), and background water matrix (W). In this framework, H, M and W were assumed to be interacted with each other and combined to determine coagulation efficiency. We investigated the feasibility of the framework to determine the treatment efficiency through mathematical models. Results showed that non-linear artificial neural network (ANN) model was a better fit to the experimental data than the linear partial least squares (PLS) model: the ANN model could explain 76% of the total variations while the PLS could only explain 71%. The PLS did not follow the variations of observed values adequately. These experiments showed that the interaction between the HMW framework components were not simple linear relationships. The ANN model was able to optimize the composition of the HMW framework improving the efficiency of DOM removal through the components of HMW such as velocity gradient (G value), coagulant dosage, solution pH, and background water matrix. Overall, HMW framework is a new classification of factors affecting coagulation, leading to a better understanding of the coagulation process and sensitivity to influencing variables.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
WATER RESEARCH
·
2013
·
IF 4.655
Zhen Yang,Han Yan,Hu Yang,Haibo Li,Aimin Li,Rongshi Cheng
The application of nanomaterials in water treatment plants has attracted significant attention recently. This study investigates the possibility of using graphene oxide (GO) as a novel flocculant to remove contaminants with different surface charges from water, including two particulate ones (kaolin and hematite) and two soluble ones (humic acid (HA) and cationic light yellow 7GL dye (7GL)). The flocculation performances of traditional polyaluminum chloride (PAC) and original graphite were also tested for comparison. Fractal theory was applied to evaluate the floc properties and explore the flocculation mechanism in combination with zeta potential measurements. For negatively charged contaminants, kaolin and HA, GO was observed to remove these contaminants successfully via the sweeping flocculation effect under acidic and neutral conditions. However, GO was less efficient than PAC. For positively charged contaminants, hematite and 7GL, the flocculation performances of GO were significantly improved than those of PAC via patching effect for hematite suspension and charge neutralization effect for 7GL solution. The results highlighted the extensive potential applicability of GO as a suitable flocculant in water treatment .
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
WATER RESEARCH
·
2024
·
IF 11.4
Panpan Li,Jianguo Zhang,Yongheng Shen,Xuefei Feng,Wenlin Jia,Mingkai Liu,Shuang Zhao
To address the problems of unstable efficiency, long treatment period, and high energy consumption during microplastics (MPs) removal by traditional coagulation–flotation technology, a gel coagulation–spontaneous flotation (GCSF) process is proposed that employs laminarin (LA) as the crosslinker and polyaluminum chloride (PAC)/polyaluminum ferric chloride (PAFC) as the coagulant to remove MPs. Herein, the effects of GCSF chemical conditions on microplastic-humic acid composite pollutants (MP-HAs) removal were investigated, and the removal mechanisms were analyzed through theoretical calculations and floc structure characterization. Results showed that an LA to PAC/PAFC ratio of 2.5:1 achieved the highest removal of HA (86 %) and MPs (93 %–99 %) in short coagulation (< 1 min) and spontaneous flotation (< 9 min) period. PAC-LA exhibited strong removal ability for MP-HAs while PAFC-LA induced fast flotation speed. The peak intensity and peak shift in Fourier-transformed infrared and X-ray photo-electron spectra indicated that the removal mechanisms of MPs include hydrogen bond adsorption and the sweeping effect, mainly relying on –OH/–C = O on the MPs surface and entrapment of gel flocs with a high degree of aggregation, respectively. The extended Derjaguin-Landau-Verwey-Overbeek calculation also revealed that interactions between PAC/PAFC-LA and MP-HAs were mainly polar interaction (hydrogen bonding) and intermolecular attraction interaction (Lifshitz-van der Waals force), and the sweep effect was reflected by intermolecular interaction. In addition, density function theory calculations indicated that –OH in LA mainly adsorbs DO through a double hydrogen bond configuration, and the crosslinking ligand FeO 6 /AlO 6 assists in DO absorption by –OH.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Wei Wu,Yingying Zhao,Junjie Qi,Chunli Li,Jing Fang,Boyang Xu,Gaojin Lyu,Gang Li,Hao Li
The synthesis and application of conventional polymeric flocculants suffer from low flocculation efficiency and toxic residues; therefore, there is an urgent need to develop green and efficient flocculants and corresponding technologies. An amphiphilic copolymer (NPL) was synthesized by a “grafting to” strategy, using acrylamide, 3-chloro-2-hydroxypropyltrimethylammonium chloride, and kraft lignin. NPL consists of a lignin core that is attached to a polyacrylamide branched chain and a cationic group, and has the properties of an amphoteric polyelectrolyte . This structure demonstrates superior flocculation performance on suspended solids. Two typical clay suspensions, kaolin and bentonite, were selected to evaluate the flocculation performance of NPL. The results showed that the turbidity of kaolin and bentonite could be reduced to 2.08 NTU and 0.31 NTU, respectively, by using NPL in combination with polymeric aluminum chloride. The synergistic effect of charge neutralization and bridging was confirmed as the main mechanism of flocculation on the two clay suspensions by a series of characterization techniques, such as zeta potential determination, particle size analysis , and focused beam reflectance measurement. The treatment of high-turbidity wastewater/feedwater with NPL was investigated, and was found to significantly improve the effluent quality. The use of NPL is efficient, environmentally friendly, and technically feasible, and shows excellent potential for the treatment of wastewater.
研究领域:
环境科学
·
材料科学
✓ 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）