Chlorination of dibenzofuran and dibenzo-p-dioxin vapor by copper (II) chloride

Dibenzofuran (DF) is formed from phenol and benzene in combustion gas exhaust streams prior to particle collection equipment. Subsequent chlorination at lower temperatures on particle surfaces is a potential source of chlorinated dibenzofuran (CDF). Gas streams containing 8% O₂ and approximately 0.1% DF vapor were passed through particle beds containing copper (II) chloride (0.5% Cu, mass) at temperatures ranging from 200 to 400 °C to investigate the potential for CDF formation during particle collection. Experiment duration was sufficient to provide an excess amount of DF (DF/Cu=3). The efficiency of DF chlorination by CuCl₂ and the distribution of CDF products were measured, with effects of temperature, gas velocity, and experiment duration assessed. Results of a more limited investigation of dibenzo-p-dioxin (DD) chlorination by CuCl₂ to form chlorinated DD (CDD) products are also presented.The efficiency of DF/DD chlorination by CuCl₂ was high, both in terms of CuCl₂ utilization and DF/DD conversion. Total yields of Cl on CDF/CDD products of up to 0.5 mole Cl per mole CuCl₂ were observed between 200 and 300 °C; this suggests that nearly 100% CuCl₂ was utilized, assuming a conversion of two moles of CuCl₂ to CuCl per mole Cl added to DD/DF. In a short duration experiment (DF/Cu=0.3), nearly 100% DF adsorption and conversion to CDF was achieved. The degree of CDF chlorination was strongly dependent on gas velocity. At high gas velocity, corresponding to a gas–particle contact time of 0.3 s, mono-CDF (MCDF) yield was largest, with yields decreasing with increasing CDF chlorination. At low gas velocity, corresponding to a gas–particle contact time of 5 s, octa-CDF yield was largest. DF/DD chlorination was strongly favored at lateral sites, with the predominant CDF/CDD isomers within each homologue group those containing Cl substituents at only the 2,3,7,8 positions. At the higher temperatures and lower gas velocities studied, however, broader isomer distributions, particularly of the less CDD/CDF products, were observed, likely due to preferential destruction of the 2,3,7,8 congeners.     

硫氰酸汞分光光度法测定空气中氯化氢空白值偏高原因分析

通过实验,证明了硫氰酸汞分光光度法测定空气中氯化氢空白值偏高的主要原因,是由于两种显色剂之间相互反应引起的。因此,在测定过程中,显色剂的加入量必须十分准确。     

钢铁盐酸酸洗废酸生产三氯化铁新工艺

简述以了钢铁盐酸酸洗废酸为原料，氧气氧化法生产ＦｅＣｌ３的原理和工艺，试验结果表明，该工艺较氯气氧化法安全，无毒，生产成本有较大幅度下降，产品质量符合国家标准ＧＢ１６２１－７９的指标。     

从钢铁酸洗废液制备聚合氯化铁及其应用研究

以钢铁酸洗废液和废铁屑为原料，测定了Fe^3 和Fe^2 含量，把过量的废铁屑加入钢铁酸洗废液中，使整个溶液还原成氯化亚铁溶液。采用氯酸钠氧化法，在(60～70)℃范围内经氧化、水解、聚合，然后加入一定量的稳定剂制得聚合氯化铁(PFC)溶液，讨论了影响聚合反应的主要因素。对炼油厂废水进行处理，合成的聚合氯化铁的处理效果明显优于市售聚合硫酸铁和三氯化铁。     

聚合物在沉淀法处理氨氮废水中的助凝作用

在采用化学沉淀法处理氨氮废水时,添加聚合物能提高了悬浮物的效率,从而节约了沉淀剂的使用量降低了处理成本.研究考查在沉淀剂中添加聚丙烯酰胺(PAM)、聚合氯化铝(PAc)对氨氮去除的影响.结果表明:在pH值为9.3,主要离子的物质量之比为1:1:1、聚丙烯酰胺添加量为20mg/L或聚合氯化铝添加量为200mg/L的条件下,处理初始浓度为1000mg/L的氨氮废水,均可使氨氮去除率可达到99%以上,PAM和PAC的助凝作用综合比较,添加20mg/L可以使氨氮率较未加入时提高5.38%.     

聚合氯化铝中Al_(13)形态水解稳定性的研究

采用聚丙烯酰胺凝胶柱层析法分离纯化聚合氯化铝(PAC)中的Al13形态,并采用Al-Ferron逐时络合比色法对比研究了Al13形态、PAC和Al13三种样品水解稳定性。研究结果表明Al13形态无论是对于稀释倍数、介质的pH值和水解时间都具有较高的水解稳定性,是给水和废水处理中的一种较为有效的Al形态。     

混凝-吸附法预处理垃圾渗滤液的研究

垃圾渗滤液是一种成分复杂的有毒有害有机废水，主要污染物是有机物．重金属和氨氮。通常采用联合工艺进行处理。笔者研究了混凝一吸附法预处理垃圾渗滤液。试验中采用聚合氯化铝作为混凝剂．最佳投药量为500mg／L：吸附剂采用自制的改性膨润土。结果表明：渗滤液中CODCr的去除率可达79％，氨氮的去除率达46％：重金属的去除率为53％～98％。     

聚硅氯化铝混凝剂除油效果的试验

制备不同碱化度和不同Ａｌ／Ｓｉ摩尔比的系列聚硅氯化铝作为混凝剂，实验考察了Ｂ，Ａｌ／Ｓｉ摩尔比及ＰＨ值对除油效果的影响，并考察了ＰＡＳＣ去除ＣＯＤ的效果。结果表明，Ｂ对ＰＡＳＣ混凝除油效果影响较大，随Ｂ值增大，除油效果提高；Ａｌ／Ｓｉ摩尔比对ＰＡＳＣ混凝除油效果影响较小；     

分析废水中化学需氧量时消除氯离子干扰的方法改进

对含氯离子废水化学需氧量测定技术进行了改进，提出了一种用硝酸银消除干扰的新方法。     

聚合氯化铝(PAC)对腐殖酸有机溶胶混凝机理的探讨

采用一定铝总量［Ａｌ］Ｔ的不同羟铝比（ｒ＝［ＯＨ］／［Ａｌ］）的ＰＡＣ溶液对有机溶胶进行混凝实验．结果表明，聚合氯化铝表面张力（σ）与有机溶胶的ＣＯＤ去除率呈正相关．根据溶液表面张力与溶质水合能力的关系和不同羟铝比的聚合氯化铝中各种羟铝配离子的相对含量，探讨聚合氯化铝对有机溶胶的混凝机理．