Pb(II) removal from water using Fe-coated bamboo charcoal with the assistance of microwaves

Bamboo charcoal(BC) was used as starting material to prepare iron-modified bamboo charcoal(Fe-MBC) by its impregnation in FeCl 3 and HNO 3 solutions simultaneously,followed by microwave heating.The material can be used as an adsorbent for Pb(Ⅱ) contaminants removal in water.The composites were prepared with Fe molar concentration of 0.5,1.0 and 2.0 mol/L and characterized by means of N 2 adsorption-desorption isotherms,X-ray diffraction spectroscopy(XRD),scanning electron microscopy coupled with energy dispersive X-ray spectrometry(SEM-EDS),Fourier transform infrared(FT-IR) and point of zero charge(pH pzc) measurements.Nitrogen adsorption analyses showed that the BET specific surface area and total pore volume increased with iron impregnation.The adsorbent with Fe molar concentration of 2 mol/L(2Fe-MBC) exhibited the highest surface area and produced the best pore structure.The Pb(Ⅱ) adsorption process of 2Fe-MBC and BC were evaluated in batch experiments and 2Fe-MBC showed an excellent adsorption capability for removal Pb(Ⅱ).The adsorption of Pb(Ⅱ) strongly depended on solution pH,with maximum values at pH 5.0.The ionic strength had a significant effect on the adsorption at pH < 6.0.The adsorption isotherms followed the Langmuir isotherm model well,and the maximum adsorption capacity for Pb(Ⅱ) was 200.38 mg/g for 2Fe-MBC.The adsorption processes were well fitted by a pseudo second-order kinetic model.Thermodynamic parameters showed that the adsorption of Pb(Ⅱ) onto Fe-MBC was feasible,spontaneous,and exothermic under the studied conditions,and the ion exchange mechanism played an significant role.These results have important implications for the design of low-cost and effective adsorbents in the removal of Pb(Ⅱ) from wastewater.     

Soil microbial community structure and function responses to successive planting of Eucalyptus

Many studies have shown soil degradation after the conversion of native forests to exotic Eucalyptus plantations. However, few studies have investigated the long-term impacts of short-rotation forestry practices on soil microorganisms. The impacts of Eucalyptus successive rotations on soil microbial communities were evaluated by comparing phospholipid fatty acid （PLFA） abundances, compositions, and enzyme activities of native Pinus massoniana plantations and adjacent 1st, 2nd, 3rd, 4th generation Eucalyptus plantations. The conversion from P. massoniana to Eucalyptus plantations significantly decreased soil microbial community size and enzyme activities, and increased microbial physiological stress. However, the PLFA abundances formed ＂U＂ shaped quadratic functions with Eucalyptus plantation age. Alternatively, physiological stress biomarkers, the ratios of monounsaturated to saturated fatty acid and Gram＋ to Gram- bacteria, formed ＂∩＂ shaped quadratic functions, and the ratio of cy17：0 to 16： 1ω7c decreased with plantation age. The activities of phenol oxidase, peroxidase, and acid phosphatase increased with Eucalyptus plantation age, while the cellobiobydrolase activity formed ＂U＂ shaped quadratic functions. Soil N：P, alkaline hydrolytic nitrogen, soil organic carbon, and understory cover largely explained the variation in PLFA profiles while soil N：P, alkaline hydrolytic nitrogen, and understory cover explained most of the variability in enzyme activity. In conclusion, soil microbial structure and function under Eucalyptus plantations were strongly impacted by plantation age. Most of the changes could be explained by altered soil resource availability and understory cover associated with successive planting of Eucalyptus. Our results highlight the importance of plantation age for assessing the impacts of plantation conversion as well as the importance of reducing disturbance for plantation management.     

Waste oyster shell as a kind of active filler to treat the combined wastewater at an estuary

Estuaries have been described as one of the most difficult environments on Earth. It is difficult to know how to treat the combined wastewater in tidal rivers at the estuary, where the situation is very different from ordinary fresh water rivers. Waste oyster shell was used as the active filler in this study in a bio-contact oxidation tank to treat the combined wastewater at the Fengtang Tidal River. With a middle-experimental scale of 360 ma/day, the average removal efficiency of COD, BOD, NH3-N, TP and TSS was 80.05%, 85.02%, 86.59%, 50.58% and 85.32%, respectively, in this bio-contact oxidation process. The living microbes in the biofilms on the waste oyster shell in this bio-contact oxidation tank, which were mainly composed of zoogloea, protozoa and micro-metazoa species, revealed that waste oyster shell as the filler was suitable material for combined wastewater degradation. This treatment method using waste oyster shell as active filler was then applied in a mangrove demonstration area for water quality improvement near the experiment area, with a treatment volume of 5 × 10^3 m^3/day. Another project was also successfully applied in a constructed wetland, with a wastewater treatment volume of 1 ×10^3 m^3/day. This technology is therefore feasible and can easily be applied on a larger scale,     

低氮燃烧+选择性非催化还原烟气脱硝技术(SNCR)在循环流化床锅炉脱硝工程上的应用

采用低氮燃烧+选择性非催化还原烟气脱硝技术对循环流化床锅炉烟气进行脱硝处理.烟气NOx初始浓度为280 mg/Nm3时,排放浓度低于100 mg/Nm3,去除率达65％以上.达到国家《火电厂大气污染物排放标准(GB13223-2011)》限值要求.工艺稳定运行后年处理费用为202.40万元.     

我国水质水量联合调度研究现状和发展趋势

水质和水量的联合调控是未来水资源调度和水污染控制的主要决策技术之一。文章从水资源调度入手,介绍了水质水量联合调度的概念和重要性,简析了国内外水质水量联合调度的研究现状、发展趋势以及"十一五"国内相关工作的最新进展。并对我国水质水量联合调度研究工作进行了展望。     

小飞扬草(Euphorbia thymifolia L.)中镉的亚细胞分布及化学形态

采用差速离心法和逐步提取法,分析Cd超积累植物小飞扬草根、茎、叶中Cd的亚细胞分布和化学形态。培养液中Cd浓度5mg/L和10mg/L条件下,在小飞扬草根、茎、叶中,细胞壁和细胞膜是Cd主要的结合场所,含量分别占总量的47.1%～49.0%、39.7%～41.4%、42.9%～56.2%,其次是胞液组分,含量分别占37.5%～41.4%、28.2%～40.7%、35.2%～46.8%,细胞器组分中Cd含量较少。Cd在小飞扬草根、茎、叶中均以氯化钠提取态为主,含量分别占70.5%～84.8%、72.4%～83.0%、50.0%～74.8%。根部各提取态含量依次为CNaCl>CHAC>CEtOH>CHCl>CW>CR,茎、叶中各提取态含量依次为CNaCl>CHCl>CHAC>CEtOH>CW>CR。在小飞扬草中,Cd与细胞壁和细胞膜中的果胶酸和蛋白质等物质结合固定,而进入细胞的Cd大部分与有机酸络合而隔离于液泡内,这可能是小飞扬草忍耐并超积累Cd的机制。     

压缩天然气加气站日常运营环境影响分析——以洛阳市某加气站为例

鉴于压缩天然气(CNG)加气站日常运行对周边环境影响的高风险状态,文章依据洛阳市某CNG加气站生产运营状况,对其运营过程中可能造成的环境影响进行预测、评析,并提出了合理的防范措施。     

活性焦烟气脱硫技术在大型燃煤电站的应用

本文通过分析活性焦烟气脱硫技术的主要原理、工艺流程、主要原料消耗、脱硫副产品综合利用、SO2污染物达标情况,探讨该技术在内蒙古地区大型燃煤电站脱硫工程应用的可行性.     

遥感技术在环境监测中的作用

本文对遥感(3S)技术在环境监测中的应用方法、技术等进行了论述.     

生物炭环境效应和在农业面源污染防治中的作用

生物炭能够延缓肥料养分释放,提高肥料利用率,降低肥料及土壤养分流失,从而减轻农业面源污染。同时,生物炭进入土壤中,实现碳的封存固定,减少碳排放。