城市污泥中铜锌的化学形态及其去除

利用连续提取法研究了城市污泥中铜和锌的化学形态,结果表明:污泥中铜和锌都以稳定性较好的硫化物及有机结合物、残渣态形式存在,生物毒性较小,通过适当处理后可以安全加以利用;在此基础上,研究了利用乙酸和双氧水去除污泥中铜和锌的适宜工艺条件,结果表明:在室温条件下,在pH值为4的环境中,利用添加H_2O_2的浓度为2mol/L的乙酸溶液,反应时间为4h,就可以将污泥中超过95%以上的铜和锌淋滤去除。     

新疆黄萎病发病程度不同棉田土壤细菌群落结构差异分析

新疆棉区棉花黄萎病发生危害严重,提高该病的生态防控技术对实现棉花"化肥、农药"减施增效有重要意义.文章以阿克苏、石河子和库尔勒三地棉花黄萎病不同发生程度棉田土壤为研究对象,利用高通量测序技术对土壤细菌种群结构进行研究,并分析土壤理化性质与细菌多样性及种群结构的相关性,以期揭示棉田土壤的细菌群落结构差异及主要影响因子,为...     

氨氮与镉单一和复合作用对沉水植物穗花狐尾藻和轮叶黑藻光合能力的影响

在水-土环境中,单一物质引起的污染很少,绝大多数污染是多种污染物质共存所造成的.利用碘量法测定溶解氧,研究了氨氮与镉单一和复合作用对沉水植物穗花狐尾藻和轮叶黑藻光合能力的影响.结果显示,氨氮浓度在4.0 mg·L^-1时,对轮叶黑藻有较强的胁迫作用,表现为光合作用的产氧量与呼吸作用的耗氧量均下降,而此浓度对穗花狐尾藻没有表现出胁迫作用;当镉处理浓度为0.2 mg·L^-1时,镉对2种沉水植物都表现出明显的胁迫效应,且对轮叶黑藻的胁迫作用更强;当镉与氨氮复合作用时,对轮叶黑藻产生联合毒害作用,但对穗花狐尾藻毒害作用较轻,可能原因是穗花狐尾藻所含的粗纤维比轮叶黑藻少,细胞壁上能结合重金属的位点较少,所以吸附的镉相应减少,毒性较小.实验结果表明在进行湖泊水生植物修复时,相对于轮叶黑藻,穗花狐尾藻更适合作为生态恢复的先锋物种.     

苯并(a)芘及其代谢产物的连续降解研究

在以驯化过的芽孢杆菌(BA-07)降解BaP的过程中,鉴定出2个BaP的未开环代谢产物顺式-4,5-二氢-4,5-二醇-BaP(cis-BP4,5-dihydrodiol)和顺式-7,8-二氢-7,8-二醇-BaP(cis-BP7,8-dihydrodiol).由于该产物对微生物有一定毒性,所以难于进一步降解.为提高BaP降解的同时,降低cis-BP4,5-dihydrodiol和cis-BP7,8-dihydrodiol的累积,对2种降解方法(即单纯用BA07降解和运用高锰酸钾与BA-07耦合的方法降解)进行了比较,并且优化了连续降解的参数.结果表明,①对BaP及其代谢产物的连续降解,化学氧化与微生物耦合(高锰酸钾与BA-07)的降解效果明显好于单纯利用微生物(细菌BA-07)的降解;②在同一时间取样,cis-BP4,5-dihydrodiol的残留率均高于cis-BP7,8-dihydrodiol;③当BaP的浓度为40μg/mL,培养基的最佳pH为7.0,以琥珀酸钠为共代谢底物,可以显著提高BaP降解率,降低cis-BP 4,5-dihydrodiol和cis-BP7,8-dihydrodiol的累积.同时提出了化学氧化与微生物协同的方法可以有效促进环境中持久有机污染物的连续降解.     

污水处理厂化学除磷精确控制系统研究——以山东某污水处理厂为例

我国总磷排放标准日趋严格,污水处理厂为保证出水总磷达标,过量投加化学除磷剂,造成资源浪费.为在出水水质达标的基础上节省化学除磷剂添加量,以山东某污水处理厂为例设计了化学除磷精确控制系统.在充分考虑仪器故障潜在风险的前提下,根据进水磷酸盐负荷实时调整药剂投加量,采用"前馈+反馈"控制的模式,实现加药过程的自动化及智能化....     

Decomposition kinetics of dimethyl methylphospate(chemical agent simulant) by supercritical water oxidation

Supercritical water oxidation （SCWO） has been drawing much attention due to effectively destroy a large variety of high-risk wastes resulting from munitions demilitarization and complex industrial chemical. An important design consideration in the development of supercritical water oxidation is the information of decomposition rate. In this paper, the decomposition rate of dimethyl methylphosphonate（DMMP）, which is similar to the nerve agent VX and GB（Sarin） in its structure, was investigated under SCWO conditions. The experiments were performed in an isothermal tubular reactor with a H2O2 as an oxidant. The reaction temperatures were ranged from 398 to 633℃ at a fixed pressure of 24 MPa. The conversion of DMMP was monitored by analyzing total organic carbon （TOC） on the liquid effluent samples. It is found that the oxidative decomposition of DMMP proceeded rapidly and a high TOC decomposition up to 99.99% was obtained within 11 s at 555℃. On the basis of data derived from experiments, a global kinetic equation for the decomposition of DMMP was developed. The model predictions agreed well with the experimental data.     

Variations among rice cultivars on root oxidation and Cd uptake

In order to understand the mechanisms on the variation between rice cultivars in Cd uptake and accumulation, two pot soil experiments were conducted with typical rice cultivars that varied greatly in soil Cd uptake. The experiments with six rice cultivars showed that the root oxidation abilities of rice differed with rice cultivars and also with types of the cultivars, the cultivars with indica consanguinity were significantly higher than the cultivars with japonica consanguinity. Root oxidation abilities of the rice cultivars correlated positively and significantly （P〈0.01） with their Cd concentrations and Cd quantity accumulations in rice plants. The experiments with two rice cultivars showed that significant differences also existed between the two cultivars in pot soil redox potentials, which of Shan you 63 （higher soil Cd accumulator） were significantly higher than that of Wu yun jing 7 （lower soil Cd accumulator） under different soil Cd levels, but the degrees of the differences varied with soil Cd levels. The differences were larger under soil Cd treatments than the control. The results indicate that root oxidation ability, especially in Cd contaminated soil, is one of the main mechanisms which dominate Cd uptake and accumulation by rice plant.     

染料废水处理技术研究进展

染料废水成分复杂,可生化性差,对生态危害极大,未经处理就排放将导致严重的环境问题.本文综述了染料废水各种处理技术的研究进展,包括物理处理(吸附、膜过滤),生物处理(厌氧、好氧、厌氧-好氧联合),化学处理(混凝-絮凝、电絮凝、高级氧化);总结了多种组合工艺对实际染料废水的处理效果;对比分析了各种处理技术的优缺点.最后,对...     

Chemical Composition and Sources of PM10 and PM2.5 Aerosols in Guangzhou, China

Aerosol samples of PM10 and PM2.5 are collected in summertime at four monitoring sites in Guangzhou, China. The concentrations of organic and elemental carbons (OC/EC), inorganic ions, and elements in PM10 and PM2.5 are also quantified. Our study aims to: (1) characterize the particulate concentrations and associated chemical species in urban atmosphere (2) identify the potential sources and estimate their apportionment. The results show that average concentration of PM2.5 (97.54 μg m⁻³) in Guangzhou significantly exceeds the National Ambient Air Quality Standard (NAAQS) 24-h average of 65 μg m⁻³. OC, EC, Sulfate, ammonium, K, V, Ni, Cu, Zn, Pb, As, Cd and Se are mainly in PM2.5 fraction of particles, while chloride, nitrate, Na, Mg, Al, Fe, Ca, Ti and Mn are mainly in PM2.5-10 fraction. The major components such as sulfate, OC and EC account for about 70–90% of the particulate mass. Enrichment factors (EF) for elements are calculated to indicate that elements of anthropogenic origins (Zn, Pb, As, Se, V, Ni, Cu and Cd) are highly enriched with respect to crustal composition (Al, Fe, Ca, Ti and Mn). Ambient and source data are used in the multi-variable linearly regression analysis for source identification and apportionment, indicating that major sources and their apportionments of ambient particulate aerosols in Guangzhou are vehicle exhaust by 38.4% and coal combustion by 26.0%, respetively.     

焦化废水中氨氮废水处理的应用与研究

焦化废水是一种氨氮和有机物浓度较高的难生化降解有机废水.综述了目前焦化废水处理方法中物化法、生化联合法和新型生物脱氮法的原理、应用以及研究进展情况,并指出了各种方法存在的问题.