五硫代碳酸钠处理含Cr(Ⅵ)水溶液的实验研究

采用一种新型还原剂五硫代碳酸钠(Na2CS5)处理含Cr(Ⅵ)水溶液.考察了含Cr(Ⅵ)水溶液的pH值、五硫代碳酸钠的用量、反应时间、沉淀时间和Cr(Ⅵ)的浓度等对Cr(Ⅵ)去除率的影响.结果表明,含白(Ⅵ)水溶液初始pH值和沉淀阶段溶液的pH值分别控制为1.5和8～8.5,n(Cr2O72-):n(CS52-)=1:...     

土壤重金属复合污染及其化学钝化修复技术研究进展

土壤重金属污染往往是2种或2种以上的多种重金属并存的复合污染。与单一污染相比,重金属复合污染中元素或化合物之间存在相互作用以及对生态效应的综合影响,对其污染土壤的修复具有挑战性。目前,土壤重金属污染的修复主要集中在单一元素上,而对土壤多种重金属并存的复合污染的同时修复研究较少。化学钝化修复是基于向土壤中添加稳定化剂,通...     

间歇式生物反应器填埋结构对渗滤液水质的影响研究

通过2套间歇式生物反应器填埋模拟装置开展实验,对不同填埋结构下垃圾降解前期渗滤液pH值、COD、NH 4＋-N、VFA以及渗滤液产生量的变化规律进行了对比研究。实验结果表明：间歇式生物反应器填埋方式能够有效抑制填埋初期渗滤液pH值的快速下降,渗滤液采取部分回灌能有效降低NH4＋-N浓度的积累,新鲜垃圾与半腐熟垃圾分层并...     

报废发射药降解菌种选育及降解特性

通过驯化富集培养,从长期受发射药污染的土壤中分离筛选出能以发射药为唯一碳源并具有较高降解能力的微生物混合菌群,混合菌群对发射药样品COD去除率最高可达75.6%。经进一步分离纯化,获得了5株优势菌。实验表明混合菌群的降解能力优于各单一菌种,应以混合菌群为目标菌种。混合菌群最佳降解温度为30～35℃,最佳pH值为7.0。...     

优势菌种浸取电解锰渣中锰的影响因素研究

采用电解锰废渣中分离出的一种锰抗性强的微生物Fusarium sp.浸取电解锰渣中的锰。研究了不同矿浆浓度、微生物生长活动、锰渣和培养基等对锰浸取效率的影响。结果表明,接种体积比为2%（v/v）时,矿浆浓度（m/v）对锰浸取效率影响显著,矿浆浓度过低（〈2%）或者过高（〉10%）对锰浸取效率都有不利影响。矿浆浓度为10%时锰浸取效率最高,达80%以上;微生物的生长活动对浸取过程有显著的影响;而锰渣的存在则能在一定程度上影响溶液的pH,进而影响锰浸取效率;培养基对锰浸取效率的贡献达50%左右。     

富营养化景观水体优势菌修复研究

研究了优势菌对富营养化景观水体修复作用。结果表明,投加优势菌4d后出现修复效果,20d修复效果达到最佳状态,浊度、NH3-N、CODMn、TN、TP和叶绿素a都大幅下降,溶解氧从7．2mg／L提高到10．4mg／L,叶绿素a与CODMn、TN、TP、NH2-N有较好的相关性。     

新型混凝剂聚磷氯化铝铁的表征及应用

以FeCl3·6H2O、AlCl3·6H2O和Na2HPO4·12H2O为主要原料,采用共聚工艺,制备了聚磷氯化铝铁(PPAFC)混凝剂.采用FTIR及SEM进行结构表征,推断磷酸根为与聚合氯化铝铁(PAFC)接聚,而不是磷酸盐与PAFC之间简单的物理混合.实验结果表明,以PPAFC处理含油乳化液废水、造纸废水及受污染...     

An experimental study on using rare earth elements to trace phosphorous losses from nonpoint sources

Controlling phosphorous (P) inputs through management of its sources and transport is critical for limiting freshwater eutrophication. In this study, characteristics of exogenous rare earth elements (REEs) and P and their losses with surface runoff (both in the water and sediments) during simulated rainfall experiments (83 mm h⁻¹) were investigated. The results revealed that on average most REEs (La, 94%; Nd, 93%; Sm, 96%) and P (96%) transported with sediments in the runoff. The total amounts of losses of REEs and P in the runoff were significantly correlated, suggesting the possibility of using REEs to trace the fate of agricultural nonpoint P losses.     

Spatial and seasonal variations of polycyclic aromatic hydrocarbons in Haihe Plain, China

A dynamic fugacity model was developed to simulate the spatial and seasonal variations of PAHs in Haihe Plain, China. The calculated and measured concentrations exhibited good consistency in magnitude with deviations within a factor of 4 in air and 2 in soil. The spatial distributions of PAHs in air were mainly controlled by emission while the seasonal variations were dominated by emission and gas-particle partition. In soil, the spatial distributions of PAHs were controlled by the soil organic carbon content while the seasonal variations were insignificant. The severest soil contamination was observed in Shanxi and followed by the southwest of Hebei province. Transfer fluxes of total PAHs between air and soil were calculated. The spatial distribution of air-to-soil flux was closely related to the landcover while the soil-to-air flux changed with soil organic matter content. Monte Carlo simulation was done to evaluate the uncertainty of the estimated results in air.