二步法腈纶废水有机污染物生物降解性实验研究

二步法腈纶废水中含有大量的有机污染物,包括腈类,酚类,烷烃类,酰胺类,表面活性剂及其它芳香族物质等,因此,对其中有机污染物的生物降解性进行了实验处理研究,实验对二步法腈纶废水进行了混凝沉淀预处理,A／O生物膜法处理,分析了有机物变化情况,同时也分析了有机污染物在处理工艺过程中的降解及反应机理。     

绿色织物柔软剂的合成及其生物降解性

合成了一种可生物降解的绿色织物柔软剂:N,N′-二软脂酸乙酯-N,N′-二羟乙基氯化铵,替代目前国内广泛使用的难以降解的柔软剂———双十八烷基二甲基氯化铵(D1821).利用三乙醇胺和软脂酸的酯化反应合成软脂酸三乙醇胺双酯,再利用氯乙醇季铵化合成了目的物软脂酸三乙醇胺双酯季铵盐(EPH).研究了EPH的最佳合成条件和生物降解率.采用手感评价法评价了EPH的性能,并采用活性污泥法检测了EPH的生物降解性.酯化反应的最佳工艺参数为φ(软脂酸)∶φ(三乙醇胺)=2.3∶10.0,温度为120℃,反应时间为6 h,在此条件下双酯质量分数达到50%以上.季铵化的最佳条件为φ(氯乙醇)∶φ(酯化产物)=1∶1,温度为80℃,反应时间为4 h,在此条件下季铵化率达到90%以上.一周以后EPH的生物降解率可达到90%以上,而D1821在相同条件下的降解率仅为5%.EPH在柔软性能上与D1821相当,生物降解率远远高于后者,理论上完全可以代替D1821.     

双酯基季铵盐生物降解性影响因素研究

研究了水体中双酯基季铵盐的生物降解性,测试好氧条件下曝气量、初始接种量、双酯基季铵盐起始浓度对其生物降解性能的影响.结果表明,双酯基季铵盐具有极强的生物降解性,最佳工艺条件为:曝气量15L·h-1,反应温度25℃,初始接种量160mg MLSS·L-1,双酯基季铵盐最佳起始浓度10mg DOC·L-1.此时,双酯基季铵盐10d的生物降解率为43.1%,28d的生物降解率为87.92%.     

Effect of citric acid induced deflocculation on the ultrasonic pretreatment efficiency of dairy waste activated sludge

In this investigation, the application of citric acid was explored for the removal of extracellular polymeric substance (EPS) from waste activated sludge (WAS), followed by ultrasonic pretreatment, which enhanced the subsequent anaerobic biodegradability. EPS was removed with 0.05 g/g SS of citric acid. The chemical oxygen demand (COD) solubilization and suspended solids (SS) reduction that occurred for specific energy input of 171.9 kJ/kg TS, in deflocculated (EPS removed and ultrasonically pretreated) sludges were found to be 22.70% and 20.28% and was comparatively higher, than the flocculated (with EPS and ultrasonically pretreated). The biogas yield potential of flocculated and deflocculated sludges (specific energy input – 171.9 kJ/kg TS) was found to be 0.212 L/(g VS) and 0.435 L/(g VS), respectively. Accordingly, the deflocculation and ultrasonic pretreatment improved the anaerobic biodegradability efficiently. Thus, this chemo mediated sonic pretreatment is an effective method for enhancing biodegradability and improving clean energy generation from WAS.     

Ultraviolet‐induced crosslinking of poly(butylene succinate) and its thermal property,dynamic mechanical property,and biodegradability

Crosslinking is an effective way to improve polymer properties. This paper focuses on ultraviolet‐induced crosslinking of poly(butylene succinate) (PBS) in the presence of a photoinitiator and a crosslinking agent at ambient temperature. The effects of the concentration of photoinitiator, the crosslinking agent content, and the irradiation time on the crosslink behavior were investigated. To obtain an appropriate gel fraction in different irradiation times, 3.0 wt% of photoinitiator and 10.0 wt% of crosslinking agent were proved to be the optimum choice. Furthermore, properties such as thermal properties, dynamic mechanical property, and enzymatic degradation of PBS before and after crosslinking were examined. Differential scanning calorimetry (DSC) analysis revealed that glass transition temperature (T_g) increased with increase in gel fraction, while melting temperature (T_m) and the degree of crystallinity decreased. This may be caused by the reduced molecular chain mobility and inhibited molecular motion for crystallization in crosslinked samples. The crosslinked polymer also showed improved thermal stability and dynamic mechanical property. In addition, the introduction of crosslinking retarded the enzymatic degradation rate of PBS, but it was still biodegradable. The improved properties of crosslinked PBS will extend the application of PBS. Copyright © 2009 John Wiley & Sons, Ltd.     

Transformation of Pectins into Non-Ionic or Anionic Surfactants Using a One-Pot and Cascade Mode Process

The present article describes the one-pot synthesis of double- and single-tailed surfactants by a cascade process that involves the hydrolysis/butanolysis of pectins into butyl galacturonate monosaccharides followed by transesterification/transacetalisation processes with fatty alcohols, and subsequent aqueous basic and acid treatments. The cascade mode allows the depolymerisation to proceed more efficiently, and the purification conditions are optimised to make the production of single-tailed surfactants more manufacturable. These products in a pure form or as mixtures with alkyl glycosides resulting from butanolysis and transglycosylation of pectin-derived hexoses, exhibit attractive surface-tension properties, especially for the n-oleyl ᴅ-galactosiduronic acid products. In addition, a readily biodegradability and an absence of aquatic ecotoxicity are shown for the galacturonic acid derivatives possessing an oleyl alkyl chain at the anomeric position.     

Functional initiators for the ring-opening polymerization of polyesters and polycarbonates: An overview

Functional ring-opening polymerization (ROP) initiators can instill a wide array of chemical, physical, and biological effects into a polymeric chain. Highlighting the versatility of this “active” initiator approach, a broad range of characteristics can be achieved through the use of initiators with chemistries spanning from drugs and dyes (key in the case of drug delivery or nanoparticle applications) through to radically active monomers, polymerization transfer agents, and catalysts. The selection of a suitable “active” initiator (monomers for tandem reactions, dyes, drugs, stereo-catalysts, etc.) can not only provide the final polymers with interesting application potential but also facilitate the implementation of ROP reactions in tandem with other polymerization techniques. Overall, this review will highlight that functionalities and properties can be effectively tuned by exploiting simple chemistry approaches, allowing readers to identify how these approaches could be of benefit to their own work in a range of applications including drug/gene delivery, amphiphilic bio/degradable carriers, drug/scent controlled release, and stereo-controlled polymers.     

高盐度化学制药废水预处理试验研究

采用"蒸馏+铁炭内电解+絮凝"工艺对某制药企业排放的废水进行预处理。经过蒸馏脱盐后,综合废水盐度(质量分数,下同)由7.4%降至0.15%;再采用"铁炭内电解+絮凝"工艺进行处理,内电解试验最佳工艺条件:进水pH值为3.0、铁炭比为4∶1(体积比)、停留时间为6 h,COD去除率达到26.5%;絮凝试验最佳pH值为9.0,COD去除率达到1.5%。废水经过预处理后,COD去除率达到28.0%,出水COD质量浓度(下同)降至20 988 mg/L,ρ(BOD)5/ρ(COD)由0.28提高至0.41。预处理出水厌氧可生化性试验表明,当进水COD质量浓度为9 000 mg/L左右时,容积负荷(COD)为1.0 kg/(m3.d),出水COD质量浓度降低至2 100 mg/L左右,COD去除率达到75.0%。说明该制药废水经过预处理后可生化性显著提高,为后续的生化处理创造了有利条件。     

离子液体毒性、生物降解性及绿色离子液体的设计与合成

离子液体作为溶剂或催化剂在化学反应、分离过程、电化学及其它领域中已有广泛的应用. 离子液体一直被认为是一种环境友好的“绿色溶剂”, 最近几年其潜在的毒性、生物降解性及绿色离子液体的设计与合成才引起人们的重视. 综述了近年来该领域的研究进展.     

Mechanical,Biodegradation and Morphological Properties of Sisal Fiber Reinforced Poly(Lactic Acid) Biocomposites

Sisal fiber-reinforced poly(lactic acid) (SF/PLA) biocomposites were prepared by melt mixing and subsequent compression molding. The effect of fiber content and sodium hydroxide (NaOH) concentration, used for the fiber mercerization, on the properties of the biocomposites was investigated. It was found that the SFs had a large potential for improving the mechanical properties of the biocomposites. The tensile strength and impact strength increased linearly up to a fiber content of 20%, and then decreased due to the fiber agglomeration. The water absorption was enhanced with increasing the SF content owing to the SFs containing an abundance of hydroxyl groups. The biodegradability of the SF/PLA biocomposites increased similarly. Furthermore, the mercerization led to an increase of the mechanical properties of the biocomposites, which normally depended on the fiber-matrix adhesion. The mercerization had competing effects on the water absorption and biodegradability, including not only the positive function of the improved hydrophilicity of the mercerized-SF but also the negative role of the increase of fiber-matrix interfacial adhesion. Overall, the optimum SF load for mechanical properties was 20?wt% due to a good balance between the reinforcement and distribution of the SFs, whereas the 6% NaOH concentration was optimal owing to the resulting fibers yielding the highest mechanical properties and acceptable water resistance and biodegradability.