PAC与PDMDAAC复合混凝剂去除高浊度水中有机氯

以聚合氯化铝(PAC)和聚二甲基二烯丙基氯化铵(PDMDAAC)为原料制备复合混凝剂,采用强化混凝的处理方法,对高浊度水体中有机氯(OCPs)以及浊度去除效果进行研究.考察了PAC-PDMDAAC复合比例、复合混凝剂投加量、水样初始浊度、慢速搅拌时间、pH值等因素对浊度和OCPs去除效果的影响,结合絮体分形维数和Zeta电位对去除效果进行验证.结果表明,复合比例对处理高浊水体中的OCPs以及浊度效果影响较大,PAC与PDMDAAC复合比例为5:1,投药量为1mL/L,慢速搅拌时间为15min时,OCPs和浊度去除率达到最佳;随着初始浊度的升高,水体中OCPs的去除率也随之增加,表明PAC-PDMDAAC复合混凝剂更适用于高浊度水中OCPs和浊度的去除;复合混凝剂与其他混凝剂相比,其最佳pH值范围较广,当pH值为4时,OCPs和浊度去除率达到最佳.利用絮体分形维数和Zeta电位两种表征手段对混凝效果进行进一步探讨,说明了实验结果的正确性.     

ZrO2掺杂的V2O5/TiO2催化剂表征及催化还原NOx

采用共沉淀法制备出不同锆掺杂量的钛锆复合载体(TiO2-ZrO2),运用XRD和BET研究其微观结构,结果显示钛锆物质的量之比1∶1时复合载体具有最大的比表面积,可达256.01 m.2g-1.以此为载体制备了V2O5/TiO2-ZrO2催化剂,并添加少量CeO2对其改性.采用XRD、BET、H2-TPR、原位FT-IR等手段研究其活性组分的表面分散状态、氧化还原特性和表面酸性.结果显示,V2O5高度分散在载体上;与纯V2O5相比,复合载体上V2O5的还原峰向低温方向发生了偏移;催化剂表面包含了大量的B酸和L酸.模拟氨气催化还原NO(NH3-SCR)的脱硝反应活性测试表明,V2O5/TiO2-ZrO2催化剂具有较好的热稳定性和较宽的活性窗口,少量CeO2的加入提高了催化剂的低温活性.     

利用植物复合床技术处理工业污水

选取风车草、蝴蝶兰、吊兰、小纸莎、菖蒲、香根草6种植物作为人工湿地植物,砾石、活性炭、河沙、砾石+河沙、活性炭+河沙、活性炭+砾石共6种填料作为人工湿地填料,进行不同植物和不同填料组合处理某胶水厂洗釜过程产生的工业废水能力的实验研究.结果表明,在相同的进水水质和水力负荷条件下,从经济成本角度考虑,蝴蝶兰与活性炭+河沙组合较好,对CODCr、氨氮的去除率分别达到95%、99%,出水水质符合DB44/26—2001广东省地方标准水污染物排放限制标准一级标准.该技术处理效果好,操作简单,易维护,适合推广.     

纳米氧化物粒子对PVDF中空纤维膜结构与性能的影响

采用相转化法制备纳米氧化物/聚偏氟乙烯复合中空纤维膜,讨论了纳米氧化钛和氧化铝粒子对PVDF膜结构和性能的影响.应用牛血清白蛋白截留实验、扫描电子显微镜、傅立叶红外光谱分别对不同膜的分离性能、微观结构和晶相组成进行了分析.结果表明,复合膜的性能与纯PVDF膜相比有显著地改善,其中纯PVDF膜、Al₂O₃/PVDF和TiO₂/PVDF复合膜对牛血清白蛋白的截留率分别为3.27%、67.20%和86.67%,复合膜的水通量则较纯PVDF膜分别提高2.3倍和2.6倍.氮气吸附实验测定的孔径分布进一步表明复合膜的孔径分布变窄,孔径变小.     

复合光合细菌对鱼塘水氨态氮H2S的去除效应

采用厌氧光照富集法培养光能有机异养型光合细菌A液和光能无机自养型光合细菌B液,将A液和B液配合成复合光合细菌,将其投放到鱼塘水中,结果表明按2%投放复合光合细菌对鱼塘水净化效果最佳,其中对NH3—N去除率88.89%;对H2S去除率91.67%。     

Molecular level toxicological evaluation of a dental composite implanted in albino rats

Dental composite (DC) resins are synthetic resins which are used as restorative material or adhesives in dentistry. Monomers and other components released into the oral environment from the DC material even after polymerization might affect the surrounding tissues and even the whole body gradually. Biocompatibility of DC has to be stringently evaluated since the fillings are in close contact with mucosa, tooth, and pulp. Common difficulties with various current dental materials include allergies, chemical leakage from the material, and pulpal irritation which are due to the byproducts of chemical reactions during different stages of material hardening. Dental Products Laboratory of Sree Chitra Tirunal Institute for Medical Sciences and Technology developed a new BIS-GMA-based DC. In this study the oxidative stress induced by this DC material in vivo was tested for a period of 1, 4, 8, 26, or 52 weeks in albino rats. Dental materials were implanted intramuscularly into the gluteus muscle and oxidative biomarkers such as lipid peroxidation, 8-oxo-deoxyguanosine (8-OHdG) concentration, and total glutathione content analyzed. Data showed no significant changes in antioxidant defense system and 8-OHdG levels in nuclear DNA of the tissue. Serum biochemical results confirmed that animals were in normal functioning physiological state.     

锂离子电池用新型复合聚合物电解质膜的性能研究

聚合物电解质膜是影响锂离子电池性能的重要因素,通过对聚合物的改性,能够改善聚合物电解质膜综合性能.本文以偏氟乙烯-六氟丙烯共聚物[P(VDF-HFP)]为基,以N甲基吡咯烷酮(NMP)作溶剂,γ-丁内酯(γ-BL)作添加剂,用倒相湿法制备出复合聚合物电解质膜,并对其离子传递、膜结构和电化学性能进行了研究.用限制扩散方法测定了该电解质膜的锂离子扩散系数为5.68×10-10 cm2·s-1;用稳态极化法测定了该电解质膜的迁移数为0.61;用交流阻抗法测得该电解质膜的室温最高电导率可达1.73×10-3S·cm-1.测试结果表明,该聚合物电解质膜具有较好的离子传输性质和电化学性能.     

多重复合加强型石膏材料的研制

从石膏的水化及硬化原理出发,通过添加有机物和无机物对石膏粉进行改性,并以石膏为基体,讨论了石膏与各种加强材料所形成的复合材料的抗压及抗折性能,从而寻找一种新型材料以解决当前化工产业生产的大量副产品——石膏的回收利用问题。     

麦秸基木质陶瓷/凹凸棒石复合材料制备与性能表征

介绍了以麦秸秆、凹凸棒石为原料,以酚醛树脂、固化剂为辅料,按照不同的配比进行混合、干燥、热压,而后采用高温烧结工艺,制备新型复合碳材料。试验制备了各种不同原料配比以及不同烧结温度下的材料,并对材料的物理强度、密度、气孔率、强度、电阻率等性能进行了测试,对其性能表征、形成机理和形成规律进行分析,初步探讨了原料选择、原料配比、碳化温度等参数对制备工艺以及复合材料性能的影响,确定了当麦秸秆∶凹凸棒石=2∶1和3∶1,温度为700～800℃时,材料的各物理性能较为理想。实验证明麦秸秆为原材料制备凹凸棒石的可行性,为麦秸秆的资源化利用、凹凸棒石的应用以及木质陶瓷复合材料的研究开辟了新的研究方向。     

Optimizing Liquid Effluent Monitoring at a Large Nuclear Complex

Effluent monitoring typically requires a large number of analytes and samples during the initial or startup phase of a facility. Once a baseline is established, the analyte list and sampling frequency may be reduced. Although there is a large body of literature relevant to the initial design, few, if any, published papers exist on updating established effluent monitoring programs. This paper statistically evaluates four years of baseline data to optimize the liquid effluent monitoring efficiency of a centralized waste treatment and disposal facility at a large defense nuclear complex. Specific objectives were to: (1) assess temporal variability in analyte concentrations, (2) determine operational factors contributing to waste stream variability, (3) assess the probability of exceeding permit limits, and (4) streamline the sampling and analysis regime. Results indicated that the probability of exceeding permit limits was one in a million under normal facility operating conditions, sampling frequency could be reduced, and several analytes could be eliminated. Furthermore, indicators such as gross alpha and gross beta measurements could be used in lieu of more expensive specific isotopic analyses (radium, cesium-137, and strontium-90) for routine monitoring. Study results were used by the state regulatory agency to modify monitoring requirements for a new discharge permit, resulting in an annual cost savings of US $223,000. This case study demonstrates that statistical evaluation of effluent contaminant variability coupled with process knowledge can help plant managers and regulators streamline analyte lists and sampling frequencies based on detection history and environmental risk.