有机硅生产废水的处理及膜污染控制

采用三级过滤—反渗透膜脱盐—多效蒸发联合工艺处理有机硅生产废水,并对反渗透膜的污染控制进行了研究。实验结果表明:高压膜脱盐率为96%左右,低压膜脱盐率为95%左右;膜系统COD去除率基本上稳定在98.25%,出水COD稳定在60 mg/L以下。针对膜污染问题,采用在线冲洗与不定期清洗相结合,有效改善了反渗透膜的污染状况,延长了膜的使用寿命。     

A Review of the Fate and Effects of Silicones in the Environment

Silicones are well-known useful materials varying in structure, reactivity, and chemical and physical properties, but they all contain a covalent bond between the silicon atom and an organic group. Most common of these polymers are those based on polydimethylsiloxane (PDMS) having a siloxane (Si–O–Si) repeat unit and two methyl groups on each silicon atom. All these polymers are manmade, and the organosilicon linkage is not found in nature. It was therefore erroneously assumed that these polymers do not degrade naturally in the environment. It is the purpose of this review to refute this myth and to describe the degradation processes of PDMS in the environment and any potential ecological impact on the terrestrial, aquatic, and atmospheric compartments. Although it was found that minor degradation takes place by hydrolysis of PDMS to dimethylsilandiol followed by oxidation of the methyl group to aldehyde and ultimately to CO₂ by Arthobacter and Fusarium oxysporium schlechtendahl, the major degradation processes are abiotic. High molecular weight PDMS are initially depolymerized by soil hydrolysis of the siloxane bonds to yield organosilanol terminated oligomers. These organosilanols and low molecular weight linear PDMS and cyclics are evaporated into the atmosphere and are oxidized there by hydroxyl radicals to benign silica, water, and CO₂.     

废弃线路板热解油合成改性酚醛树脂

以废弃线路板热解油为原料,采用碱溶—中和—萃取工艺提取其中以苯酚为主的粗酚,并合成改性酚醛树脂。合成硼酸改性酚醛树脂的优化工艺条件为n(粗酚)∶n(外加苯酚)=2∶3,n(粗酚+外加苯酚)∶n(甲醛)∶n(NaOH)∶n(硼酸)=1∶1.5∶0.15∶0.17;合成有机硅改性酚醛树脂的优化工艺条件为n(粗酚)∶n(外加苯酚)=2∶3,n(粗酚+外加苯酚)∶n(甲醛)∶n(NaOH)∶n(正硅酸乙酯)=1∶1.3∶0.1∶0.1。所合成的硼酸改性和有机硅改性酚醛树脂的主要性能指标均满足YB/T4131—2005《耐火材料用酚醛树脂》中牌号为PFn-5301的热固性液体树脂性能的要求。     

铁炭微电解-水解酸化-接触氧化法处理有机硅废水的研究

针对有机硅废水的特性,采用铁炭微电解预处理、水解酸化和接触氧化组合工艺处理有机硅废水。废水经铁炭微电解预处理后COD去除率达40%;水解酸化处理后COD去除率达30%;接触氧化处理后COD去除率达70%;当系统进水COD为750 mg/L时,经过组合工艺处理后,出水COD可降至100 mg/L以下,达到了工业废水排放标准。     

铁屑流化床预处理-催化氧化-混凝沉淀组合工艺处理有机硅废水

采用铁屑流化床预处理、负载活性炭催化剂催化氧化和混凝沉淀组合工艺处理有机硅废水。废水经铁屑流化床预处理后Cu^2＋的去除率达99．90％,COD去除率达23．9％;负载活性炭催化剂催化氧化的最佳工艺条件：催化剂质量浓度为0．5g/L,H202质量浓度为2400mg/L,不投加FeSO4,反应时间为60min,体系pH为3-4,COD去除率达82％。催化氧化后的废水经混凝沉淀处理,调节pn为8-9,可达标排放。