Laboratory Research into Permeable Reactive Barriers for Groundwater Remediation

Permeable Reactive Barriers (PRB) is a new technology for groundwater pollution remediation. Contaminants are converted into harmless by products in situ as the polluted water passes through a reactive wall. Experimental results demonstrate how reactive media can be used to remove contaminants from polluted water by laying the reactive wall across the flow direction of the water. The most comprehensively studied and applied reactive barrier type uses granulated Zero Valent Iron (ZVI) particles. In this process elemental iron provides a reducing environment which makes reductive dechlorination of chlorinated organic compounds feasible or changes redox sensitive metals, so that they are immobilized by a precipitation reaction. A reactive wall column which is made up of ZVI, sand and zeolite has shown the highest contaminant removal capacity compared to the other two which have different components. The potentials of ZVI, zeolite and Powdered Activated Carbon (PAC) to remove contaminants are due to their different physico-chemical proper-ties which make them to "sorb"metal contaminants. The results of this experiment show that PRB technology is an efficient method for the treatment of leachate-contaminated groundwater.     

"黑色"非晶形三价铁羟基氧化物及其对有害物质的吸附

利用硝酸铁与氨水之间的水解反应,生成了一种新的"黑色"非晶形三价铁羟基氧化物 (FeOOH).该物质在室温下稳定,有较高的硬度,其比表面积约为 300 m2/g,零电荷点 (PZC)在 pH 7～ 8之间.根据 M(o)ssbauer谱的鉴定,它具有四方纤铁矿(β-FeOOH)的结构特征. FeOOH和它与各溶质的表面配合物的 X射线光电光谱结果表明, FeOOH与 Pb、 Zn和GrO(4/2-)之间的反应是物理吸附,而与PO(4/3-)和AsO(4/3-)之间的反应是化学吸附. 3个阴离子及 2个阳离子的吸附等温式结果表明,该三价铁羟基氧化物的吸附能力比常见的铁羟基氧化物强 3倍.磷酸盐与砷酸盐之间的竞争反应结果表明,磷酸盐与 FeOOH的反应比砷酸盐强烈.     

电气石复合材料微孔吸滤剂在香烟"降焦减害"中的应用

对不同产地黑电气石化学组成及其极化吸附特性进行了分析,同时制备了应用于香烟“降焦减害”的电气石复合材料微孔吸滤剂,直观检验了吸滤剂的“降焦减害”功效。实验结果表明：电气石复合材料微孔吸滤剂对香烟烟气中的焦油及其有害成分具有良好的吸附作用。初步分析了电气石吸滤剂的“降焦减害”作用机理。     

Developing sorbent standards for spill response: Effects of the Oil Pollution Act of 1990 and the Free Trade Agreement

For the past five years the Millsaps Sorbent Laboratory has been actively engaged in developing standards for initial and long-term oil spill remedial technologies. As a voting member of the American Society of Testing Materials (ASTM) F-20 Committee, Canadian General Standards Board, and the US Coast Guard Sorbents Task Force, the laboratory has been engaged in developing useful, pragmatic protocols for various chemical and physical sorbent and filtration technologies driven by the deadlines imposed by the Oil Pollution Act of 1990 (OPA 90). The open border approach to certification of technologies and products promulgated by the US/Canadian Free Trade Agreement has placed the US users and producers of such products and systems in a unique and tenuous position. Canadian standards and goals are grandfathered into the United States under this agreement and products have official US government certification based on Canadian regulations. This situation is unfavorable to the US domestic environment and economy for several specific scenarios. Included in these scenarios are: abundant warmwater zones and inland waters of the US versus Canada, the basic chemical variation between Canadian and US crude oils, the different generally accepted remediation technologies in the US versus Canadian, and the technology validation procedures prior to purchase inherent to both countries.     

Laboratory Research into Permeable Reactive Barriers for Groundwater Remediation

1IntroductionAs industrialization is gaining roots throughout the world and population is increasing, there is the accompanying problem of waste disposal from vari-ous sources. Due to inefficient waste management processes, subsurface water bodies are being con-taminated by various kinds of chemicals (Soliman etal., 1998). PRB is a comparatively new groundwater treat-ment technology where contaminants are converted into harmless by products in situ as the polluted water passes through a re…     

Variation Characteristics of Ambient NMHCs at Shangdianzi and Lin''an Regional GAW Sites

In order to study the variation characteristics of concentration of the atmospheric non-methane hydrocarbons (NMHCs) in background area of China, the atmospheric concentrations of NMHCs were measured at Lin'an (LA) regional GAW (Global Atmosphere Watch) Station (30°250'N , 119° 440'E; 132.0 m ASL)and Shangdianzi (SDZ) regional GAW Station (40°190'N , 117°07'E; 286.5 m ASL) with the sorbent sorption/thermal desorption/gas chromatographic method. Totally 145 samples were collected during the period of October 2003 and July 2004. Among the 52 NMHC species of C2-C10 detected there were 26 alkanes,17 alkenes, and 9 aromatics. The average concentrations of total NMHCs (TNMHCs) at LA and SDZ were(238.5±126.0) 10-9C and (278.7±185.5) 10-9C, respectively. The results showed the ambient concentrations of TNMHCs at LA regional GAW Station increased notably over the last decade. The compositions of NMHCs at SDZ and LA were relatively similar. The proportions of alkanes, alkenes, and aromatics for SDZ and LA were in ranges of (27.3±4.0)%, (10.3±3.5)%, and (62.5±4.8)%,respectively, with features of vehicle exhaust emissions. The concentrations of NMHCs at the two sites showed obvious diurnal and seasonal variations. The TNMHC concentrations in October-November were high at the two sites, and relatively low in April and July. The diurnal variation patterns at the sites were different. The high TNMHC concentrations at SDZ normally appeared in evening and night, but appeared in morning at LA. The TNMHCs concentrations at the two sites were significantly influenced by the meteorological condition. The high TNMHC concentration associated with the local wind from the urban areas or trafic in upper reaches.     

粉煤灰的火法改性及其在废水处理中的应用

应用正交实验设计理论,在粉煤灰中添加助熔剂(Na2CO3),在800~900℃的高温下熔融,然后与NaOH溶液混合进行火法改性。多种实验方式对比得知,火法改性粉煤灰是废水中重金属最好的吸附剂。火法改性后粉煤灰处理废水的最优改性产品配比为:原状粉煤灰与Na2CO3的比例为1∶2;所用NaOH的浓度为1 mol/L;烘干温度为100℃。改性前后的扫描电镜照片及X射线衍射图的对比分析结果表明,粉煤灰的吸附性孔道随温度升高而增多,温度达300℃时为最佳,其比表面积增大,同时产生新的矿物相(A型和Na-P型沸石),吸附能力提高。而温度高于300℃时,吸附孔道被烧得塌陷或堵死,因而降低了吸附率。     

Variation Characteristics of Ambient NMHCs at Shangdianzi and Lin＇an Regional GAW Sites

In order to study the variation characteristics of concentration of the atmospheric non-methane hydrocarbons (NMHCs) in background area of China, the atmospheric concentrations of NMHCs were measured at Lin'an (LA) regional GAW (Global Atmosphere Watch) Station (30°25'N, 119°44'E; 132.0 m ASL) and Shangdianzi (SDZ) regional GAW Station (40°19'N, 117°07'E; 286.5 m ASL) with the sorbent sorp-tion/thermal desorption/gas chromatographic method. Totally 145 samples were collected during the period of October 2003 and July 2004. Among the 52 NMHC species of C2-C10 detected there were 26 alkanes, 17 alkenes, and 9 aromatics. The average concentrations of total NMHCs (TNMHCs) at LA and SDZ were (238.5±126.0)×KT9C and (278.7±185.5)x10-9C, respectively. The results showed the ambient concentrations of TNMHCs at LA regional GAW Station increased notably over the last decade. The compositions of NMHCs at SDZ and LA were relatively similar. The proportions of alkanes, alkenes, and aromatics for SDZ and LA were hi ranges of (27.3±4.0)%, (10.3±3.5)%, and (62.5±4.8)%, respectively, with features of vehicle exhaust emissions. The concentrations of NMHCs at the two sites showed obvious diurnal and seasonal variations. The TNMHC concentrations in October-November were high at the two sites, and relatively low in April and July. The diurnal variation patterns at the sites were different. The high TNMHC concentrations at SDZ normally appeared in evening and night, but appeared in morning at LA. The TNMHCs concentrations at the two sites were significantly influenced by the meteorological condition. The high TNMHC concentration associated with the local wind from the urban areas or traffic in upper reaches.     

AMA吸附剂吸附铬(Ⅵ)的性能研究及应用

用凹凸棒石粘土改性制备了AMA吸附剂，对其吸附铬(Ⅵ)的性能进行了较系统地研究。选择了吸附铬(Ⅵ)的最佳条件，用来处理含铬(Ⅵ)废水，铬(Ⅵ)的去除率在96％以上，铬(Ⅵ)的残余浓度小于0．5mg/L，符合国家的排放标准。可以在废水治理中推广应用。