Microplastics have caused great concern worldwide recently due to their ubiquitous presence within the marine environment. Up to now, most attention has been paid to their sources,distributions, measurement methods, a...Microplastics have caused great concern worldwide recently due to their ubiquitous presence within the marine environment. Up to now, most attention has been paid to their sources,distributions, measurement methods, and especially their eco-toxicological effects. With microplastics being increasingly detected in freshwater, it is urgently necessary to evaluate their behaviors during coagulation and ultrafiltration(UF) processes. Herein, the removal behavior of polyethylene(PE), which is easily suspended in water and is the main component of microplastics, was investigated with commonly used Fe-based salts. Results showed that although higher removal efficiency was induced for smaller PE particles, low PE removal efficiency(below 15%) was observed using the traditional coagulation process, and was little influenced by water characteristics. In comparison to solution pH, PAM addition played a more important role in increasing the removal efficiency, especially anionic PAM at high dosage(with efficiency up to 90.9%). The main reason was ascribed to the dense floc formation and high adsorption ability because of the positively charged Fe-based flocs under neutral conditions. For ultrafiltration, although PE particles could be completely rejected,slight membrane fouling was caused owing to their large particle size. The membrane flux decreased after coagulation; however, the membrane fouling was less severe than that induced by flocs alone due to the heterogeneous nature of the cake layer caused by PE, even at high dosages of Fe-based salts. Based on the behavior exhibited during coagulation and ultrafiltration, we believe these findings will have potential application in drinking water treatment.展开更多
The reaction of aromatic aldehydes 1 with 5, 5-dimethyl-1, 3-cyclohexandione 2 was investigated in this paper by using [bmim][BF4] as the reaction medium. It was found that when the reaction was carried out in the pre...The reaction of aromatic aldehydes 1 with 5, 5-dimethyl-1, 3-cyclohexandione 2 was investigated in this paper by using [bmim][BF4] as the reaction medium. It was found that when the reaction was carried out in the presence of catalytic amount of FeCl3·6H2O, xanthenediones 3 was obtained in high yields. On the other hand, when a combination of trimethylchlorosilane (TMSCl) and FeCl3·6H2O was employed as the catalyst, the reaction afforded ring-opening derivatives of xanthenediones 4 with high efficiency.展开更多
An environmentally and economically sustainable synthesis of 2-benzoxazyl ketones and 2-benzothiazyl ke- tones through FeC13·6H2O catalyzed tandem reactions of alkynyl bromides with 2-amino（thio）phenols in [bmi...An environmentally and economically sustainable synthesis of 2-benzoxazyl ketones and 2-benzothiazyl ke- tones through FeC13·6H2O catalyzed tandem reactions of alkynyl bromides with 2-amino（thio）phenols in [bmim]BF4 has been developed. Remarkable advantages of this new synthetic strategy include high efficiency, readily available starting materials, and recyclable catalyst and reaction medium.展开更多
基金supported by the National Key R&D Program of China (No. 2016YFC0400802)the National Natural Science Foundation for Young Scientists of China (No. 51608514)a special fund from the Key Laboratory of Drinking Water Science and Technology, Research Center for EcoEnvironmental Sciences, Chinese Academy of Sciences (No. 17Z03KLDWST)
文摘Microplastics have caused great concern worldwide recently due to their ubiquitous presence within the marine environment. Up to now, most attention has been paid to their sources,distributions, measurement methods, and especially their eco-toxicological effects. With microplastics being increasingly detected in freshwater, it is urgently necessary to evaluate their behaviors during coagulation and ultrafiltration(UF) processes. Herein, the removal behavior of polyethylene(PE), which is easily suspended in water and is the main component of microplastics, was investigated with commonly used Fe-based salts. Results showed that although higher removal efficiency was induced for smaller PE particles, low PE removal efficiency(below 15%) was observed using the traditional coagulation process, and was little influenced by water characteristics. In comparison to solution pH, PAM addition played a more important role in increasing the removal efficiency, especially anionic PAM at high dosage(with efficiency up to 90.9%). The main reason was ascribed to the dense floc formation and high adsorption ability because of the positively charged Fe-based flocs under neutral conditions. For ultrafiltration, although PE particles could be completely rejected,slight membrane fouling was caused owing to their large particle size. The membrane flux decreased after coagulation; however, the membrane fouling was less severe than that induced by flocs alone due to the heterogeneous nature of the cake layer caused by PE, even at high dosages of Fe-based salts. Based on the behavior exhibited during coagulation and ultrafiltration, we believe these findings will have potential application in drinking water treatment.
基金This work was financially supported by NNSFC(No.20273019)the Science Foundation of Henan Normal University for Young Scholars(No.0307032).
文摘The reaction of aromatic aldehydes 1 with 5, 5-dimethyl-1, 3-cyclohexandione 2 was investigated in this paper by using [bmim][BF4] as the reaction medium. It was found that when the reaction was carried out in the presence of catalytic amount of FeCl3·6H2O, xanthenediones 3 was obtained in high yields. On the other hand, when a combination of trimethylchlorosilane (TMSCl) and FeCl3·6H2O was employed as the catalyst, the reaction afforded ring-opening derivatives of xanthenediones 4 with high efficiency.
文摘An environmentally and economically sustainable synthesis of 2-benzoxazyl ketones and 2-benzothiazyl ke- tones through FeC13·6H2O catalyzed tandem reactions of alkynyl bromides with 2-amino（thio）phenols in [bmim]BF4 has been developed. Remarkable advantages of this new synthetic strategy include high efficiency, readily available starting materials, and recyclable catalyst and reaction medium.
