The electrokinetic characteristics and coagulation behaviors of polyaluminum silicate chloride (PASiC) and polyaluminum chloride (PAC) were studied and compared by streaming current (SC) measurement and jar test metho...The electrokinetic characteristics and coagulation behaviors of polyaluminum silicate chloride (PASiC) and polyaluminum chloride (PAC) were studied and compared by streaming current (SC) measurement and jar test method. The experimental results showed that the interaction between polysilicic acid characterized negative charge and hydrolyzed aluminum species result in a decrease of the charge neutralizing ability of PASiC, compared to PAC. The decrease has a close relationship with the basicity ( B ) and Al/Si molar ratio in PASiC. The less the B value and the Al/Si molar ratio, the lower the charge neutralizing ability of PASiC is. In contrast, the preparation technique for PASiC affects the charge-neutralization of PASiC to a smaller extent. In addition, compared with PAC, PASiC may enhance aggregating efficiency and give better coagulating effects.展开更多
In recent years,engineered nanoparticles,as a new group of contaminants emerging in natural water,have been given more attention AlCl3 In order to understand the behavior of nanoparticles in the conventional water tre...In recent years,engineered nanoparticles,as a new group of contaminants emerging in natural water,have been given more attention AlCl3 In order to understand the behavior of nanoparticles in the conventional water treatment process,three kinds of nanoparticle suspensions,namely multi-walled carbon nanotube-humic acid（MWCNT-HA）,multiwalled carbon nanotube-N,N-dimethylformamide（MWCNT-DMF） and nano TiO2-humic acid（TiO2-HA） were employed to investigate their coagulation removal efficiencies with varying aluminum chloride（AlCl3） concentrations AlCl3 Results showed that nanoparticle removal rate curves had a reverse ＂U＂ shape with increasing concentration of aluminum ion（Al^（3＋） ）AlCl3 More than 90% of nanoparticles could be effectively removed by an appropriate Al^（3＋） concentration AlCl3 At higher Al^（3＋） concentration,nanoparticles would be restabilized AlCl3 The hydrodynamic particle size of nanoparticles was found to be the crucial factor influencing the effective concentration range（ECR） of Al^（3＋） for nanoparticle removal AlCl3 The ECR of Al^（3＋） followed the order MWCNT-DMF 〉 MWCNT-HA 〉 TiO2-HA,which is the reverse of the nanoparticle size trend AlCl3 At a given concentration,smaller nanoparticles carry more surface charges,and thus consume more coagulants for neutralization AlCl3 Therefore,over-saturation occurred at relatively higher Al^（3＋） concentration and a wider ECR was obtained AlCl3 The ECR became broader with increasing p H because of the smaller hydrodynamic particle size of nanoparticles at higher p H values AlCl3 A high ionic strength of Na Cl can also widen the ECR due to its strong potential to compress the electric double layer AlCl3 It was concluded that it is important to adjust the dose of Al^（3＋） in the ECR for nanoparticle removal in water treatment.展开更多
Membranes for gas separation have developed significantly in the last twenty years,however,there is still a need for high temperature and chemically resistant membranes that exhibit good selectivity and gas permeabili...Membranes for gas separation have developed significantly in the last twenty years,however,there is still a need for high temperature and chemically resistant membranes that exhibit good selectivity and gas permeability.Our study examines the fundamental properties of polyetherketone (PEK,a thermally stable and chemically resistant polymer) membranes prepared using concentrated sulphuric acid (98% H_2SO_4) as the solvent.Non-solvents used in the work included acetic acid,ethanol,methanol,glycerol,and water....展开更多
文摘The electrokinetic characteristics and coagulation behaviors of polyaluminum silicate chloride (PASiC) and polyaluminum chloride (PAC) were studied and compared by streaming current (SC) measurement and jar test method. The experimental results showed that the interaction between polysilicic acid characterized negative charge and hydrolyzed aluminum species result in a decrease of the charge neutralizing ability of PASiC, compared to PAC. The decrease has a close relationship with the basicity ( B ) and Al/Si molar ratio in PASiC. The less the B value and the Al/Si molar ratio, the lower the charge neutralizing ability of PASiC is. In contrast, the preparation technique for PASiC affects the charge-neutralization of PASiC to a smaller extent. In addition, compared with PAC, PASiC may enhance aggregating efficiency and give better coagulating effects.
基金supported by the Hundreds Talents Program of Chinese Academy of SciencesOpen Foundation of State Key Laboratory of Environmental Criteria and Risk Assessment+1 种基金Chinese Research Academy of Environmental Sciences (SKLECRA2015OFP10)Natural Science Foundation of Heilong Jiang Province
文摘In recent years,engineered nanoparticles,as a new group of contaminants emerging in natural water,have been given more attention AlCl3 In order to understand the behavior of nanoparticles in the conventional water treatment process,three kinds of nanoparticle suspensions,namely multi-walled carbon nanotube-humic acid（MWCNT-HA）,multiwalled carbon nanotube-N,N-dimethylformamide（MWCNT-DMF） and nano TiO2-humic acid（TiO2-HA） were employed to investigate their coagulation removal efficiencies with varying aluminum chloride（AlCl3） concentrations AlCl3 Results showed that nanoparticle removal rate curves had a reverse ＂U＂ shape with increasing concentration of aluminum ion（Al^（3＋） ）AlCl3 More than 90% of nanoparticles could be effectively removed by an appropriate Al^（3＋） concentration AlCl3 At higher Al^（3＋） concentration,nanoparticles would be restabilized AlCl3 The hydrodynamic particle size of nanoparticles was found to be the crucial factor influencing the effective concentration range（ECR） of Al^（3＋） for nanoparticle removal AlCl3 The ECR of Al^（3＋） followed the order MWCNT-DMF 〉 MWCNT-HA 〉 TiO2-HA,which is the reverse of the nanoparticle size trend AlCl3 At a given concentration,smaller nanoparticles carry more surface charges,and thus consume more coagulants for neutralization AlCl3 Therefore,over-saturation occurred at relatively higher Al^（3＋） concentration and a wider ECR was obtained AlCl3 The ECR became broader with increasing p H because of the smaller hydrodynamic particle size of nanoparticles at higher p H values AlCl3 A high ionic strength of Na Cl can also widen the ECR due to its strong potential to compress the electric double layer AlCl3 It was concluded that it is important to adjust the dose of Al^（3＋） in the ECR for nanoparticle removal in water treatment.
基金the Engineering and Physical Sciences Research Council (EPSRC,No.GR/M56876).
文摘Membranes for gas separation have developed significantly in the last twenty years,however,there is still a need for high temperature and chemically resistant membranes that exhibit good selectivity and gas permeability.Our study examines the fundamental properties of polyetherketone (PEK,a thermally stable and chemically resistant polymer) membranes prepared using concentrated sulphuric acid (98% H_2SO_4) as the solvent.Non-solvents used in the work included acetic acid,ethanol,methanol,glycerol,and water....
