The electrochemical selective reduction of NO using CoSe2@CNTs hybrid

Converting the NO from gaseous pollutant into NH₄ ⁺ through electrocatalytical reduction using cost-effective materials holds great promise for pollutant purifying and resources recycling. In this work, we developed a highly selective and stable catalyst CoSe₂ nanoparticle hybridized with carbon nanotubes (CoSe₂@CNTs). The CoSe₂@CNTs hybrid catalysts performed an extraordinary high selectivity for NH₄ ⁺ formation in NO electroreduction with minimal N₂O production and H₂ evolution. The specific spatial structure of CoSe₂ is conductive to the predominant formation of N-H bond between the N from adsorbed NO and H and inhibition of N-N formation from adjacent adsorbed NO. It was also the first time to convert the coordinated NO into NH₄ ⁺ using non-noble metal catalysis. Moreover, the original concept of employing CoSe₂ as eletrocatalyst for NO hydrogenation presented in this work can broaden horizons and provide new dimensions in the design of new highly efficient catalysts for NH₄ ⁺ synthesis in aqueous solution.

     

A comparative study of abiological granular sludge (ABGS) formation in different processes for zinc removal from wastewater

Abiological granular sludge (ABGS) formation is a potential and facile strategy for improving sludge settling performance during zinc removal from wastewater using chemical precipitation. In this study, the effect of pH, seed dosage, and flocculant dosage on ABGS formation and treated water quality was investigated. Results show that settling velocity of ABGS can reach up to 4.00 cm/s under optimal conditions, e.g., pH of 9.0, zinc oxide (ZnO) seeds dosage of 1.5 g/l, and polyacrylamide (PAM) dosage of 10 mg/l. More importantly, ABGS formation mechanism was investigated in NaOH precipitation process and compared with that in bio-polymer ferric sulfate (BPFS)–NaOH precipitation process regarding their sludge structure and composition. In the NaOH precipitation process, ABGS formation depends on some attractions between particles, such as van der Waals attraction and bridging attraction. However, during the BPFS–NaOH sludge formation process, steric repulsion becomes dominant due to the adsorption of BPFS on ZnO seeds. This repulsion further causes extremely loose structure and poor settling performance of BPFS–NaOH sludge.     

海底油气管道的泄漏及预防

介绍了海底油气管道铺设特点,分析了海底管道破裂的原因主要是第三方损害,其次还有物理损伤、机械损伤、管线材质缺损、材料疲劳、管线内外表面腐蚀、不可抗力和外界条件变化等。提出了海底管道泄漏的有效预防措施,主要包括预防第三方损害和管线腐蚀、提高泄漏检测和监测能力、制定应急响应计划、鼓励公众参与、迅速实施应急响应计划五部分。