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Study of flocculation performance and mechanism of ultrafine montmorillonite particles with NPAM

Wang Lujun, Min Fanfei, Chen Jun, Wang Ting, Zhou Zhuang

Physicochemical Problems of Mineral Processing

2022

Vol. 58, iss. 3

art. no. 147790

Ultrafine montmorillonite particles are the main clay minerals in industrial wastewater. In order to explore the flocculation performance and mechanism of flocculant with montmorillonite, the effects of nonionic polyacrylamide (NPAM) dosage and molecular weight on flocculation effect were studied using a flocculation sedimentation experiment. The morphology of flocs was observed by metallographic microscope and scanning electron microscope, and the microscopic adsorption mechanism was studied utilizing density functional theory (DFT). The results show that the best reagent system for the montmorillonite sample is that the molecular weight of NPAM is 14 million and the added amount is 100 g/t. The floc size increases with rising NPAM dosage, forming a unique multi-level compact space network structure through polymer bridging. The adsorption energy of acrylamide on the Na-(001) surface of montmorillonite is -108.81 kJ/mol, which is significantly higher than -50.66 kJ/mol on the None-(001) surface. Hydrogen bonding is not the main reason for the adsorption of acrylamide on the montmorillonite surface. NPAM mainly causes the flocculation and sedimentation of montmorillonite through the processes of polymer bridging and electrostatic attraction. This study can provide a theoretical basis for the design and synthesis of new flocculants.

Nitrogen-doped Carbon Catalyst by Ultrasonic for Electrocatalytic CO2 Reduction

Liu Jianfeng, Wang Ting, Zhang Zhenhai, Ning Kai, Yin Shibin, Yuan Binxia

Polish Journal of Chemical Technology

2020

Vol. 22, nr 3

24--28

The electrocatalytic reduction of carbon dioxide into valued chemicals such as formic acid has the most promising potential in applying renewable energy for useful materials and mitigating the greenhouse effect. However, the studies still focus on developing catalysts with low price and high catalytic properties. In this study, nitrogen atoms were decorated into carbon structure by a unique ultrasonic method, then the nitrogen-doped carbon material was applied as catalyst in CO2 reduction, it exhibited excellent electrochemical activity, 4 times higher than the normal method. The improved activity should be attributed to the interaction between nitrogen and carbon atoms through analysis.

Catalytic oxidation of lignin to aromatics over salen-porphyrin complex as a biomimetic catalyst

Lu Xu-Jie, Zhou Xue-Fei, Zhu Zheng-Liang, Sun Yali, Tang Kai, Lei Fu-Hou, Liu Zu-Guang, Wang Ting

Drewno : prace naukowe, doniesienia, komunikaty

2019

vol. 62, nr 203

67--80

The aim of this work is to enable increased production of aromatics by the use of salen-porphyrin complex (ZnPSC6) as a binuclear catalyst for the catalytic oxidation of Indulin AT lignin. Catalytic activity was enhanced by the increase in active sites, as confirmed by the results observed in the conversion of lignin model compounds and Indulin AT lignin compared with processes using the mononuclear complexes Zn(salen) and Zn(Phe-TPP). The yields of long and convoluted aromatics from the catalytic oxidation of Indulin AT lignin with ZnPSC6 reached high values after reaction at 80°C for 24 h. Notably, the formation of vanillin was promoted by the increase in active sites over ZnPSC6. This was followed by a significant decrease of β-O-4 linkages and refractory condensed substructures in the lignin, induced by ZnPSC6. This may be expected to be an important area for further study.