Sorption of tylosin and sulfamethazine on solid humic acid

Tylosin(TYL) and sulfamethazine(SMT) are ionizable and polar antimicrobial compounds,which have seeped into the environment in substantial amounts via fertilizing land with manure or sewage. Sorption of TYL and SMT onto humic acid(HA) may affect their environmental fate. In this study, the sorption of TYL and SMT on HA at different conditions(pH, ionic strength) was investigated. All sorption isotherms fitted well to the Henry and Freundlich models and they were highly nonlinear with values of n between 0.5 and 0.8, which suggested that the HA had high heterogeneity. The sorption of TYL and SMT on HA decreased with increasing p H(2.0–7.5), implying that the primary sorption mechanism could be due to cation exchange interactions between TYL~+/SMT~+ species and the functional groups of HA.Increasing ionic strength resulted in a considerable reduction in the K_d values of TYL and SMT,hinting that interactions between H bonds and π–π EDA might be an important factor in the sorption of TYL and SMT on HA. Results of Fourier transform infrared(FT-IR) and ~13C-nuclear magnetic resonance(NMR) analysis further demonstrated that carboxyl groups and O-alkyl structures in the HA could interact with TYL and SMT via ionic interactions and H bonds,respectively. Overall, this work gives new insights into the mechanisms of sorption of TYL and SMT on HA and hence aids us in assessing the environmental risk of TYL and SMT under diverse conditions.     

地下水铀污染的原位微生物还原与固定:在美国能源部田纳西橡树岭放射物污染现场的试验

总结了美国斯坦福大学和橡树岭国家实验室等在美国能源部田纳西州橡树岭综合试验基地进行的铀污染原位微生物修复阶段性试验结果.本试验利用微生物以乙醇为电子供体还原地下水和沉积物中的六价铀为不溶解的四价铀,使之原位固定化.随后通过加入溶解氧和硝酸盐来试验微生物还原后的地下水层中还原固定态铀的稳定性.通过预处理和长期间隔注入乙醇...     

HAS土壤固化剂对电镀污泥处理效果的研究

本课题采用HAS土壤固化剂代替传统固化基材对电镀污泥进行常温固化处理 ,在实现污泥无害化的基础上 ,探讨利用电镀污泥研制一种性能优良的“免烧免蒸”护坡砖的可行性。实验研究表明 ,固化块的机械性能、抗冻 融性能、耐干 湿性能均满足护坡砖的要求 ,并且浸出液中重金属离子的浓度在国家允许的范围内。因此 ,该固化工艺开辟了电镀污泥资源化利用的新途径     

非活性黑根霉菌对废水中重金属离子的吸附

为探讨发酵工业中废弃的菌丝体黑根霉菌（Ｒｈｉｚｏｐｕｓｎｉｇｒｉｃａｎｓ）对水中重金属离子的吸附特性,考察ｐＨ、浓度、共存离子等因素对吸附能力的影响,进行了实验室吸附试验,绘制出吸附等温线,并由Ｌａｎｇｍｕｉｒ曲线和Ｆｒｅｕｎｄｌｉｃｈ曲线求出相应参数。对化学改性前后的黑根霉进行了吸附对比。初步分析了吸附机理。结果表明,黑根霉在ｐＨ＝３—６．５范围内,对Ｐｂ２＋、Ｃｕ２＋、Ｍｎ２＋、Ｃｒ（ＶＩ）几种主要重金属离子都有吸附作用,其中吸附Ｐｂ２＋能力最高,饱和吸附量可达８８ｍｇ／ｇ。经化学改性的黑根霉可不同程度地提高吸附能力。用０．５ｍｏｌ／ＬＨＣＩ和ＮａｏＨ可以洗脱和再生。     

额济纳天然胡杨林水分利用效率动态变化研究

黑河下游的额济纳绿洲是我国西北地区重要的生态屏障,也是当地人民赖以生存的自然资源,然而由于种种原因,这片绿洲正在衰败并且有消亡的危险.胡杨是典型的潜水旱中生植物,它虽然有较强的耐大气干旱、耐盐碱能力,其生长发育与水分条件的优劣有着十分密切的关系.本文通过研究额济纳天然胡杨的叶水势、蒸腾速率、光合速率的变化规律,综合分析其水分利用效率与叶水势的相关关系,了解胡杨树体内水分运移关系,为揭示胡杨生存现状和合理利用水资源提供理论依据,为合理保护额济纳绿洲胡杨林提供科学支持.     

Efficient microwave-assisted photocatalytic degradation of endocrine disruptor dimethyl phthalate over composite catalyst ZrOx/ZnO

A highly active ZrOx/ZnO catalyst for microwave-assisted photocatalytic (MW/PC) degradation of endocrine disruptor dimethyl phthalate (DMP) has been prepared via cetyltrimethylammonium assisted hydrothermal method. The ZrOx/ZnO was characterized by XPS, XRD, UV-Vis, BET and SEM techniques. The XPS result showed that Zr oxides with different valences (+2, +3, +4) co-existed in ZrOx/ZnO. By using the ZrOx/ZnO (0.1 g), the TOC removal efficiency of DMP (100 mL of 50 mg/L) was 88% after 30 min reaction, which was about 15% higher than P25 TiO2. It was found that the removal process of DMP by MW/PC followed pseudo first-order kinetics in all cases, and ZrOx/ZnO significantly accelerated the degradation of DMP. The degradation half-life time of DMP was shortened 45% compared with P25 TiO2. A possible catalytic mechanism was proposed based on microwave response and interfacial charge transfer. ZrOx/ZnO could be reused for six times without obvious decrease in catalytic activity. The study offers new insights into designing highly efficient catalysts for MW/PC process and is applicable for MW/PC environmental remediation.     

江西省环境与经济耦合关系研究

根据江西省环境与经济的发展状况,综合运用熵值法和线性加权法对区域环境与经济发展水平作出评价,并利用协同论和容量耦合概念建立两种数学模型对江西省环境与经济耦合关系进行研究.结果表明:江西省经济实力在不断增强,环境质量先快速下降后略微上升,环境与经济的耦合关系在不断增强,15年内一直处于协调发展水平,且发展水平在不断提高.对比分析两种模型,发现两模型用于评价区域环境与经济耦合关系均具有一定的科学性和合理性,但基于协同论的协调度和协调发展度模型更能反映江西省环境与经济的耦合关系.     

Effect of vegetation change from native broadleaf forest to coniferous plantation on selected soil properties

The objective of this study was to examine the effects of vegetation change from a native broadleaf forest to a coniferous plantation on selected soil properties, including soil texture, pH, organic matter, total nitrogen (N), total phosphorus (P), exchangeable cations (Ca²⁺, K⁺, Na⁺), and cation exchange capacity (CEC). Results showed that the amount of clay particles, Ca²⁺, and K⁺ values significantly increased, whereas Na⁺, total N, and organic matter and soil pH values decreased on the treatment plot after vegetation change. Soil acidity also increased and soil textural group changed from moderately fine-textured soils (clay loam) to medium-textured soils (loam) under both control and treatment plots. Organic matter, total N, and Na⁺ values increased, whereas Ca²⁺ concentration decreased through time on the control plot. Soil pH, total P, K⁺, and CEC did not show significant changes through time on the control plot.     

黄浦江上游支流污染负荷分析及防治对策

对黄浦江上游１４条主要支流的水资源特性，水量、水质和工业，、生活、农田径流、禽畜、泵站等污染源的现状进行了大量的调查，对２０００年各污染源排放量进行了预测。同时，对支流区域内污染物的产生量与影响支流水体污染的成因，及支流的污染负荷进行了分析，提出了相应的水污染综合防治对策。