Environmental Chemistry Letters - About one tenth of humans are impacted by water shortages around the globe. Water resilience is worsening under climate change because intensifying weather... 相似文献
A process combining catalyzed Fe(0)-carbon microelectrolysis (IC-ME) with activated carbon (AC) adsorption was developed for advanced reclaimed water treatment. Simultaneous nitrate reduction and chemical oxygen demand (COD) removal were achieved, and the effects of composite catalyst (CC) addition, AC addition, and initial pH were investigated. The reaction kinetics and reaction mechanisms were calculated and analyzed. The results showed that CC addition could enhance the reduction rate of nitrate and effectively inhibit the production of ammonia. Moreover, AC addition increased the adsorption capacity of biorefractory organic compounds (BROs) and enhanced the degradation of BRO. The reduction of NO3?–N at different pH values was consistently greater than 96.9%, and NH4+–N was suppressed by high pH. The presence of CC ensured the reaction rate of IC-ME at high pH. The reaction kinetics orders and constants were calculated. Catalyzed iron scrap (IS)-AC showed much better nitrate reduction and BRO degradation performances than IS-AC and AC. The IC-ME showed great potential for application to nitrate and BRO reduction in reclaimed water.
In recent years, steppe degradation in North China has become a serious environmental problem. Most research on steppe degradation is conducted at the level of communities or at the scale of small regions. To better understand the spatio-temporal variation and driving factors of grassland degradation, monitoring and analysis at broad regional scales are needed. This paper systematically describes the state and characteristics of steppe degradation at the Xilinhot plateau, makes an in-depth empirical analysis of the natural and man-made causes leading to degradation, and analyzes what driving factors have influenced degradation in this typical steppe region over the last 20?years. Ten biophysical and socio-economic variables, including altitude, slope, precipitation, temperature, soil conditions, distance to river, distance to highway, population density, sheep unit density, and fencing policy, were evaluated on their impact on observed patterns of degradation. The results indicate that all of these factors had a significant influence on the process of steppe degradation. During the first 10?years, from 1991 to 2000, steppe degradation increased, but after 2000, the degradation trend has, to some extent, reversed. The analysis indicates that the measures taken by the government, such as fencing vulnerable areas, played an important role in this change. The results advance the understanding of grassland degradation and contribute to constructing an empirical and theoretical base for grassland management and planning. 相似文献