双氧水催化氧化中Cu/γ-Al_2O_3催化剂的稳定性研究

针对废水湿式双氧水催化氧化,采用浸渍法制备Cu催化剂,研究非均相Cu催化剂在常温常压湿式双氧水催化氧化中的稳定性与失活问题。研究表明,催化剂制备条件及催化氧化反应条件对催化剂中Cu2＋溶出均有影响。研究同时表明,催化剂失活与活性组分流失和活性组分被有机中间产物覆盖有关,高温焙烧可对催化剂再生。     

土壤有机质测定方法的进展

对土壤有机质测定的3种主要方法及特点和应用范围进行了论述和评价。认为上壤有机质测定方法改进的目标不仅仅是简便、快速、廉价,还应包括无污染。     

Preparation of metal-doped Cu–Mn/HTS-1 catalysts and their mechanisms in efficient degradation of toluene

In order to study their synergistic catalytic effects in toluene degradation, CuMn_2O_4/HTS-1(HTS-1 was a titanium silicon molecular sieve), Cu_(0.7)Mn_2Y_(0.3)O_x/HTS-1 and Cu_(0.7)Mn_2Ce_(0.3)O_x/HTS-1 catalysts were prepared by the impregnation method.The textural properties, redox properties and acidity of the catalysts were characterized by X-ray diffractometer(XRD),transmission electron microscopy(TEM), scanning electron microscopy(SEM), H_2 temperature-programmed reduction(H_2-TPR), X-ray photoelectron spectroscopy(XPS),frustrated total internal reflection(FT-IR), ammonium temperature-programmed desorption(NH_3-TPD) and pyridine adsorption internal reflection(Py-IR) measurements.The potential roles of Lewis acid sites(activating dioxygen) were discussed, and the experimental results indicated that the most efficient route for toluene degradation over Cu_(0.7)Mn_2Ce_(0.3)O_x/HTS-1(toluene conversion rate of 90%(T99) = 295℃) was ascribed to regulation of the synergistic effects of redox properties(activating molecular toluene) and Lewis acid sites(activating dioxygen).The Mars–Van–Krevelen(MVK) model was adopted to describe the reaction process of toluene oxidation, which gave an in-depth view into the toluene degradation over CuMn_2O_4/HTS-1, Cu_(0.7)Mn_2Y_(0.3)O_x/HTS-1 and Cu_(0.7)Mn_2Ce_(0.3)O_x/HTS-1.In addition, the synergistic effects between redox properties and Lewis acid sites were studied in detail.     

Impact of urban innovation on urban green development in China’s Yangtze River Economic Belt: perspectives of scale and network

Environmental Science and Pollution Research - Understanding whether and how urban innovation offers a sound solution to the dilemma of urban green development is a crucial response to mitigate the...     

Effectiveness of cascading time series models based on meteorological factors in improving health risk prediction

Environmental Science and Pollution Research - Meteorological factors, which are periodic and regular in a long run, have an unignorable impact on human health. Accurate health risk prediction...     

Precise regulation of acid pretreatment for red mud SCR catalyst: Targeting on optimizing the acidity and reducibility

• The optimum SCR activity was realized by tuning the acid pretreatment. • Optimized catalysts showed NO_x conversion above 90%. • The NH₃ and NO adsorption capacity of Al-O₃-Fe is stronger than Fe-O₃-Fe. • The formation of almandine consumes Fe³⁺ and Al³⁺ and weakens their interaction. Red mud (RM), as an alkaline waste, was recently proved to be a promising substitute for the SCR catalyst. Dealkalization could improve the acidity and reducibility of red mud, which were critical for SCR reaction. However, the dealkalization effect depended on the reaction between acid solution and red mud. In this study, we realized the directional control of the chemical state of active sites through tuning the acid pretreatment (dealkalization) process. The pretreatment endpoint was controlled at pH values of 3–5 with diluted nitric acid. When the pH values of red mud were 3 and 5 (CRM-3 and CRM-5), activated catalysts showed NO_x conversion above 90% at 275°C–475°C. The high initial reaction rate, Ce³⁺/(Ce³⁺ + Ce⁴⁺) ratio, and surface acidity accounted for the excellent SCR performance of CRM-5 catalyst. Meanwhile, more Fe³⁺ on the CRM-3 surface improved the NH₃ adsorption. There was a strong interaction between Al and Fe in both CRM-5 and CRM-3 catalysts. DFT results showed that the adsorption capacity of the Al-O₃-Fe for NH₃ and NO is stronger than that of Fe-O₃-Fe, which enhanced the NO_x conversion of the catalyst. However, the almandine was formed in CRM-4, consumed part of Fe³⁺ and Al³⁺, and the interaction between Al and Fe was weakened. Also, deposited almandine on the catalyst surface covered the active sites, thus leading to lower NH₃-SCR activity.     

Source apportionment of bioavailable trace metals in soil based on chemical fractionation and its environmental implications

Environmental Science and Pollution Research - The bioavailable trace metals are closely related to environmental safety and human health, which might have different source characteristics from the...     

Preparation and characterization of modified dual network dust suppression gel based on sodium alginate and soluble starch

Aiming at the problems of complex environment and serious dust pollution in large open-pit coal yards, a dust suppression gel with a dual network structure was prepared by modifying the soluble starch and sodium alginate with iron ions. The changes of functional groups, thermal stability, and morphology structure before and after the reaction were analyzed by FTIR, TG-DSC, and SEM, and the formation mechanism of the dual network was revealed by XPS. Furthermore, the water absorption and water retention experiments proved that the dual network structure is more conducive to water retention than the single-layer network. According to molecular dynamics simulations and contact angle experiments, gel and adsorbed water molecules can approach coal dust molecules on their own to contact, wet, and combine with coal dust. The adhesion test proved that the dust suppression gel with iron ions had better adhesion to dust. The anti-freezing test shows that the dust suppression gel has good anti-freezing performance. The antifreeze test shows that the dust suppression gel still has excellent freeze–thaw resistance at the test temperature of??-20℃. The mechanical property test shows that the dust suppressant gel can prevent the product from being damaged by external force. The acid and alkali resistance experiments showed that the acid and alkali resistance of the gel was improved under the condition of iron ion modification, and the flying of coal powder was effectively prevented. This research provides a new theoretical idea for coal dust control in complex environment.

     

公众投诉、环境规制对工业技术创新的影响研究

在碳达峰碳中和背景下,工业如何实现环保、科技与经济的共同进步已成为中国亟待解决的难题。本文基于中国工业2008—2018年的省级面板数据,建立动态面板模型,采用系统广义矩（GMM）估计方法,对现代环境治理体系中公众投诉、环境规制及工业技术创新三者的关系进行了探讨。结果表明：①公众投诉、环境规制成为直接推动工业技术创新产出的重要因素;②环境规制在公众投诉影响工业技术创新产出的过程中发挥着部分中介作用;③产业集聚强化了公众投诉对工业技术创新的促进作用。因此,完善公众投诉制度、提升公众环保意识、加强环境规制强度、优化政策支持及提升产业集聚程度,对于工业实现经济绩效与环境绩效的双赢具有重要意义。