Effects of rainfall on surface environment and morphological characteristics in the Loess Plateau

Environmental Science and Pollution Research - Slope failure is a one of major process that causes severe landform variation and environment variation, and slope failure has become a major hidden...     

竹制填料生物接触氧化工艺处理污染河水简

针对受污染的湖溪河水质特征,以传统弹性塑料填料做对比,研究以竹球和竹丝为填料的生物接触氧化工艺,考察填料的挂膜时间、生物量和污水处理效果;确定连续曝气和间歇曝气时反应器的最优运行工况：连续曝气时为HRT=7.5 h,DO=3 mg/L;间歇曝气时为厌氧1.2 h、好氧6.3 h交替运行。实验结果表明,与弹性塑料填料相比,竹制填料挂膜速度快,竹球填料的水处理效果最好;连续曝气最优工况下竹球填料反应器中COD、TN、NH₃-N和TP的平均去除率分别为66.7%、47.9%、57.1%和30.6%;间歇曝气最优工况下竹球填料反应器中COD、TN、NH₃-N和TP的平均去除率分别64.08%、39.95%、60.7%和54.68%;竹制填料可替代传统的塑料填料作为生物接触氧化工艺的载体填料。     

高水无机材料防灭火性能影响因素研究与实践*

为进一步揭示高水无机材料抑制煤自燃机理,将其更好地应用于煤矿防灭火领域,开展高水无机材料流动渗透性能实验与高水无机材料抑制煤堆自燃实验,研究不同水灰比和不同空隙率条件下高水无机材料浆液流动渗透规律和高水无机材料浆液煤堆自燃降温规律。结果表明:高水无机材料浆液的水灰比和煤块间的间隙宽度对其流动渗透性能有显著影响,煤堆不同径向距离处的温度均呈现出开始迅速降低、之后缓慢降低的2个降温阶段。三河尖矿防灭火工程实践应用表明水灰比28∶1的高水无机材料浆液有较好的防灭火效果。     

Efficient metoprolol degradation by heterogeneous copper ferrite/sulfite reaction

Metal/sulfite systems are currently used for SO ₄ ^?? generation and oxidative removal of organic contaminants. However, homogeneous metal/sulfite systems are limited because their working pHs must be acidic and metal ions cannot be separated from the bulk reaction solution. As a consequence, these drawbacks have severely limited the application of metal/sulfite systems in real conditions. To address these issues, we tested the use of copper ferrite (CuFe₂O₄), a ferromagnetic nanoparticle, to catalyze sulfite oxidation for the degradation of the metoprolol drug. The reaction mechanism was investigated by electron spin resonance, X-ray photoelectron spectroscopy, and radical quenching assay. The effects of pH, CuFe₂O₄, and sulfite dosages were also assessed. Results show that SO ₄ ^?? was the primary radical responsible for metoprolol degradation. Higher pHs induced more metoprolol degradation using CuFe₂O₄/sulfite. Moreover, CuFe₂O₄ remained morphologically intact and catalytically active after four batches of recycling. Overall, our findings show that CuFe₂O₄/sulfite can effectively degrade water contaminants in alkali pH and withhold catalyst activity after multiple reuses, therefore addressing the issues associated with homogeneous metal/sulfite systems.     

Utilization of solar energy in sewage sludge composting: Fertilizer effect and application

Three reactors, ordinary, greenhouse, and solar, were constructed and tested to compare their impacts on the composting of municipal sewage sludge. Greenhouse and solar reactors were designed to evaluate the use of solar energy in sludge composting, including their effects on temperature and compost quality. After 40 days of composting, it was found that the solar reactor could provide more stable heat for the composting process. The average temperature of the solar reactor was higher than that of the other two systems, and only the solar reactor could maintain the temperature above 55 °C for more than 3 days. Composting with the solar reactor resulted in 31.3% decrease in the total organic carbon, increased the germination index to 91%, decreased the total nitrogen loss, and produced a good effect on pot experiments.     

单线态氧氧化水中对氨基苯胂酸的研究

阿散酸(p-ASA)作为一种有机砷饲料添加剂被广泛应用于养殖业以促进动物生长.因其几乎不被动物体吸收转化而易进入到养殖业环境中,其氧化降解则会向环境中释放无机砷而造成环境砷污染.以LED灯(λ=660 nm)为激发光源、亚甲基蓝(MB)为光敏剂,产生单线态氧(1O2),研究1O2对水中p-ASA的氧化降解形成无机砷的过程.同时考察体系初始p H、光照强度、光敏剂浓度等因素对反应的影响.结果表明,p-ASA经光敏反应而显著降解,并产生以As(V)为主的无机砷.p-ASA在偏碱性条件下降解显著;p-ASA降解率与光照强度呈正相关;p-ASA降解率随着光敏剂MB浓度增大先有明显提高,MB浓度大于3 mg·L-1后趋于稳定.选取糠醇(FFA)作为参考物,利用竞争动力学方法估算得出p H=10时1O2与p-ASA的反应速率常数为7.44×106L·mol-1·s-1.     

Multiple transformation pathways of p-arsanilic acid to inorganic arsenic species in water during UV disinfection

p-Arsanilic acid(p-ASA) is widely used in China as livestock and poultry feed additive for promoting animal growth.The use of organoarsenics poses a potential threat to the environment because it is mostly excreted by animals in its original form and can be transformed by UV–Vis light excitation.This work examined the initial rate and efficiency of p-ASA phototransformation under UV-C disinfection lamp.Several factors influencing p-ASA phototransformation,namely,p H,initial concentration,temperature,as well as the presence of Na Cl,NH4+,and humic acid,were investigated.Quenching experiments and LC–MS were performed to investigate the mechanism of p-ASA phototransformation.Results show that p-ASA was decomposed to inorganic arsenic(including As(Ⅲ) and As(V))and aromatic products by UV-C light through direct photolysis and indirect oxidation.The oxidation efficency of p-ASA by direct photosis was about 32%,and those by HOU and1O2 were 19% and 49%,respectively.Cleavage of the arsenic–benzene bond through direct photolysis,HOU oxidation or1O2 oxidation results in simultaneous formation of inorganic As(Ⅲ),As(IV),and As(V).Inorganic As(Ⅲ) is oxidized to As(IV) and then to As(V) by1O2 or HOU.As(IV) can undergo dismutation or simply react with oxygen to produce As(V) as well.Reactions of the organic moieties of p-ASA produce aniline,aminophenol and azobenzene derivatives as main products.The photoconvertible property of p-ASA implies that UV disinfection of wastewaters from poultry and swine farms containing p-ASA poses a potential threat to the ecosystem,especially agricultural environments.     

竹制填料生物接触氧化工艺处理污染河水

针对受污染的湖溪河水质特征,以传统弹性塑料填料做对比,研究以竹球和竹丝为填料的生物接触氧化工艺,考察填料的挂膜时间、生物量和污水处理效果;确定连续曝气和间歇曝气时反应器的最优运行工况：连续曝气时为HRT：7．5h,DO=3mg／L;间歇曝气时为厌氧1．2h、好氧6．3h交替运行。实验结果表明,与弹性塑料填料相比,竹制填料挂膜速度快,竹球填料的水处理效果最好;连续曝气最优工况下竹球填料反应器中COD、TN、NH3-N和TP的平均去除率分别为66．7％、47．9％、57．1％和30．6％;间歇曝气最优工况下竹球填料反应器中COD、TN、NH3-N和TP的平均去除率分别64．08％、39．95％、60．7％和54．68％;竹制填料可替代传统的塑料填料作为生物接触氧化工艺的载体填料。     

Prolonged persulfate activation by UV irradiation of green rust for the degradation of organic pollutants

Environmental Chemistry Letters - Metal-activated persulfate is an efficient reagent for the oxidative degradation of organic contaminants. However, homogenous catalytic activation of persulfate...     

Enhanced degradation of Orange II using a novel UV/persulfate/sulfite system

Environmental Chemistry Letters - UV-activated persulfate (PS) systems have been widely employed to remove organic contaminants. However, the heavy use of persulfate may lead to secondary...