聚醚改性三硅氧烷的生物降解性能研究

通过振荡培养实验和连续活性污泥模拟实验研究了聚醚改性三硅氧烷的初级生物降解性能和最终生物降解性能,并通过水解实验考察了水解对生物降解的影响.研究发现:在振荡培养实验中,第7天时的初级生物降解度为30.6%(硫氰酸钴法)和34.5%(表面张力法);在连续活性污泥模拟实验中,降解稳定期平均初级生物降解度为32.8%(硫氰酸钴法)和34.6%(表面张力法),平均最终生物降解度为26.3%;水解对生物降解基本无影响.结果表明,聚醚改性三硅氧烷不易初级生物降解和最终生物降解.     

表面活性剂的结构与生物降解性的关系

对表面活性剂的生物降解性进行了全面的概述，着重讨论了表面活性剂的降解性能与结构的关系。表面活性剂的生物降解性主要由疏水基团决定，并随着疏水基线性程度的增加而增加，末端季碳原子会显著降低降解度，疏水链长短也影响降解性；表面活性剂的亲水基性质对生物降解度有次要的影响；乙氧基链长影响非离子表面活性剂的生物降解性；增加磺酸基和疏水基末端之间的距离，烷基苯磺酸盐的初级生物降解度增加（距离原则）。最后指出了我国今后表面活性剂生物降解度研究的发展方向。     

不同农药助剂的初级生物降解性研究

以新型复配农药助剂——松脂基表面活性剂1号和2号以及传统农药助剂壬基酚聚氧乙烯醚、松香酸聚乙二醇酯和直链十二醇聚氧乙烯醚为目标物,通过实验考察了不同类型农药助剂的初级生物降解特性。8 d的生物降解实验结果表明,松脂基表面活性剂1号的初级生物降解度为79.1%,松脂基表面活性剂2号的初级生物降解度为82.4%,松香酸聚乙二醇酯的初级生物降解度为84.2%,壬基酚聚氧乙烯醚的初级生物降解度为91.1%,直链十二醇聚氧乙烯醚的初级生物降解度大于99%。新型复配农药助剂的组成结构更为复杂,其初级生物降解度要低于直链醇类、酚类的聚氧乙烯醚及单一结构酸类的聚乙二醇酯等农药助剂。     

一种表面活性剂对活性污泥的影响及其可生物降解性的测试方法

以月桂醇聚醚硫酸酯钠(AES)、月桂醇聚醚硫酸酯铵(AESA)为例：通过污泥耗氧速率的变化了解表面活性剂对活性污泥的抑制情况；用磁力搅拌表面曝气法代替震荡培养法测试了城镇污水处理厂的活性污泥对表面活性剂的生物降解能力；用污泥负荷表征表面活性剂的初级生物降解速率，便于计算用活性污泥法处理表面活性剂至其起泡性能消失所需的时间。实验结果表明，AES、AESA浓度≥200 mg·L^-1时对活性污泥中部分微生物有抑制作用。当AES、AESA浓度≤100 mg·L^-1时，用城镇污水处理厂的活性污泥好氧处理的初级生物降解速率分别为0.06 kg AES.(kg MLSS·d)^-1、0.06 kg AESA.(kg MLSS·d)^-1；用活性污泥法好氧处理20小时后的COD_Cr去除率分别为75.7%、79.9%;AESA的可生物降解性优于AES。     

表面活性剂生物降解性能的研究进展

对表面活性剂的生物降解性能进行了全面概述。着重讨论了表面活性剂的降解性能测试方法、生物降解机理、降解动力学及用于量化分析可生物降解的同位素标记反应运移模型,并对各类表面活性剂结构与降解能力作了评价。最后,指出了我国表面活性剂生物降解度研究的发展方向。     

表面活性剂生物降解度的测定

建立和完善了表面活性剂生物降解度的测定方法，包括活性污泥的制备、培养、驯化和降解等试验过程。并以此方法对常见的阴离子和非离子表面活性剂的生物降解性进行测定，结果表明AES和异构C13醇AEO7需1d完全降解；天然醇AOS、AEO7和TX－10需2d完全降解；SAS和聚醚需3d完全降解；LAS则需4d完全降解，与文献完全吻合，验证了该方法的可靠性。该方法具有较好的重要性。     

油溶性表面活性剂生物降解度的测定

对ISO 10634-1995“水质———水介质中用于难溶有机物生物降解性能评价水溶液的制备与处理指南”推荐的方法进行逐一筛选,以期建立油溶性表面活性剂生物降解度测定的标准方法。实验结果表明,将油溶性表面活性剂超声乳化后,制备成粒径200 nm~300 nm乳液后,立即分散于水体系中进行降解,结果重复性较好,并且不影响油溶性表面活性剂生物降解度。用该方法对常见的油溶性表面活性剂的生物降解度进行了测定,结果表明大部分油溶性表面活性剂具有很好的生物降解性能;其降解规律与水溶性表面活性剂类似,疏水链长决定油溶性表面活性剂的生物降解性能,而亲水基团影响其生物降解速度。     

烷基糖苷最终生物降解性能以及影响因素的研究

在实验室条件下,用震荡培养法研究不同试验条件对烷基糖苷(以APG0810为代表)生物降解性的影响。结果表明,在浓度为30 mg/L,p H=7,不含酵母膏的培养基,微生物源为生活污水处理厂中活性污泥的条件下,烷基糖苷的初级生物降解度最大。采用密闭瓶法研究烷基糖苷的最终生物降解性能,其10 d降解率在50%左右,28 d降解率在70%以上,参照OECD 301标准,属于易生物降解有机物。     

烷基糖苷最终生物降解性能以及影响因素的研究

在实验室条件下,用震荡培养法研究不同试验条件对烷基糖苷(以APG0810为代表)生物降解性的影响。结果表明,在浓度为30 mg/L,p H=7,不含酵母膏的培养基,微生物源为生活污水处理厂中活性污泥的条件下,烷基糖苷的初级生物降解度最大。采用密闭瓶法研究烷基糖苷的最终生物降解性能,其10 d降解率在50%左右,28 d降解率在70%以上,参照OECD 301标准,属于易生物降解有机物。     

表面活性剂最终生物降解试验装置的搭建及可行性研究

搭建了与OECD 301B相适应的表面活性剂最终生物降解装置,通过对样品醋酸钠及阴离子表面活性剂LAS生物降解性测定,表明该装置研究表面活性剂最终生物降解性能的可行性。应用该装置测定APG0810,其最终生物降解率为86.5%。     

Biodegradability and aquatic toxicity of glycoside surfactants and a nonionic alcohol ethoxylate

The environmental properties of three glycoside surfactants and one alcohol ethoxylate were examined by standardized laboratory methods. All of the surfactants biodegraded extensively in aerobic screening tests and may be assumed to approach 100% removal in aerobic wastewater treatment plants, except in cases of high loadings or otherwise exceptional conditions. Anaerobic biodegradability tests showed that an ethyl glycoside monoester (EGE) and a linear alkyl polyglycoside (APG) were both mineralized (>70%) under methanogenic conditions. In contrast, a branched APG resisted anaerobic degradation, while the alcohol ethoxylate was partially mineralized by anaerobic bacteria. The EGE surfactant was most rapidly mineralized in aerobic and anaerobic biodegradability tests. None of the surfactants inhibited respiration in activated sludge at the highest concentration tested (200 mg/L). Tests with aquatic organisms showed increasing toxicity in the following order: branched APG<EGE<linear APG<alcohol ethoxylate. Negligible aquatic toxicity was observed for the branched APG, while the alcohol ethoxylate was highly toxic to examined organisms. This evaluation demonstrates that considerable variation in biodegradability and toxicity responses can be seen within structurally related glucose-based surfactants.     

Environmental Impact of Ether Carboxylic Derivative Surfactants

The ultimate aerobic biodegradability and toxicity of three ether carboxylic derivative surfactants having different alkyl chains and degrees of ethoxylation were investigated. Ultimate aerobic biodegradability was screened by means of dissolved organic carbon determinations at different initial surfactant concentrations. For comparison, the characteristic parameters of the biodegradation process, such as half-life, mean biodegradation rate, and residual surfactant concentration, were determined. Increased surfactant concentrations decreased mineralization and lengthened the estimated half-life. The results demonstrate that the ultimate aerobic biodegradability is higher for the surfactants with the shortest alkyl chain and highest degree of ethoxylation. Toxicity values of the surfactants, and their binary mixtures, were determined using three test organisms, the freshwater crustacea Daphnia magna, the luminescent bacterium Vibrio fischeri and the microalgae Selenastrum capricornutum. The toxicity is lower for the surfactants with the shortest alkyl chain and highest degree of ethoxylation. The toxicity of binary mixtures of the three ether carboxylate surfactants at a 1:1 weight ratio was also measured. The least toxic mixture is formed by the surfactants having lower individual toxicity.     

Primary aerobic biodegradation of cationic and amphoteric surfactants

The primary aerobic biodegradation of several cationic and amphoteric surfactants has been studied by using the shaking-flask degradation test and orange II spectrophotometric analysis. The results show that cationic and amphoteric surfactants can be readily biodegraded, with their degradation exceeding 94%. The degradation kinetics can be accurately described by the Boltzmann model. The relationship between structure and biodegradability is discussed. The presence of hydrophobic groups has a strong effect on the biodegradability of these surfactants. Biodegradability decreases with increasing chain length. The presence of hydrophilic groups mainly affects the degradation rate of these surfactants, but not their ultimate biodegradeability. Bio-degradability is deterred and degradation is slowed as steric hindrance increases. Degradation rates increase markedly when hydrophilic groups containing an amide bond are pres-ent.     

Primary Biodegradation of Commercial Fatty-Alcohol Ethoxylate Surfactants: Characteristic Parameters

This paper concerns the primary biodegradation of different commercial fatty-alcohol ethoxylate surfactants (FAEs), applying the OECD 301 E test for ready biodegradability. Changes were made both in the carbon-chain length of the surfactants as well as in the number of units of ethylene oxide (EO) in its molecule. The biodegradation were monitored, analysing the colony-forming units (CFU) formed during this process. From the biodegradation profiles drawn for the FAEs, parameters characteristic of the biodegradation process were defined: latency time (t _L), biodegradability at 50 h of assay (B), half-life (t _1/2), mean biodegradation rate until reaching biodegradability of 85% (V _M), and the residual concentration of the surfactant (S _R). The analysis of these parameters enabled the establishment of the influence of surfactant concentration and structure during the biodegradation process. The increase in the surfactant concentration lowered the rate of the biodegradation process and the biodegradability of the surfactant in addition to the half-life and residual concentration of the surfactant. The mean biodegradation rate, V _M, for fatty-alcohol ethoxylates increased with the number of EO units and molecular weight of the surfactant. At low initial test concentrations (less than 25 mg/L), the concentration of the residual surfactant rapidly diminished with biodegradation time. For higher concentrations, after an adaptation period of the microorganisms, the surfactant concentration declined exponentially and the biodegradation rate became far slower for all the surfactants. The parameters characteristic of the growth curves: specific growth-rate, k, and the yield of biomass production per gram of surfactant, Y _ap, made possible the quantification and corroboration of the results during the biodegradation process.

Biodegradability of nonionic surfactants: Screening test for predicting rate and ultimate biodegradation

Environmental water quality evaluations of raw materials in consumer products occupy a position of critical importance in many industries throughout the world. The rapid growth and diversity of the household detergent market requires continuous consideration of new materials needed to meet the demands of new, improved and modified products. As household cleaning products are normally disposed of as a component of domestic sewage, surface active compounds, including nonionic surfactants, would reach surface waters only as a part of a sewage effluent and would be subject to the same degree of biological treatment as the balance of the waste. For this reason, evaluations of such new materials include an environmental assessment in which biodegradability testing of organic materials is an important first step. Biodegradability characteristics of nonionic surfactants, as a class, are generally more difficult to ascertain because of wide structural diversity and a usual lack of functional groups. Such determinations usually involve intricate and laborious test methods which necessitate development of analytical techniques for each degradation product of a given material. A method has been developed, modified and used in our laboratory, that provides, after reasonable opportunity for biological acclimation, a measure of the rate and degree of ultimate biodegradation (conversion to CO₂ and H₂O). This method, which uses simple equipment, has been used to assess the biodegradability of a wide variety of nonionic surfactants, without necessitating the development of specific analytical methods for each surfactant under consideration. Additionally, this method can be adapted to measure degradation under conditions of anaerobiosis or low temperature.     

Biodegradation of different carboxylate types of cleavable surfactants bearing a 1,3-dioxolane ring

The biodegradability of new carboxylate types of “acid-sensitive” cleavable surfactants bearing a 1,3-dioxolane ring was measured by the biochemical oxygen demand (BOD) method in the presence of activated sludge. The result for sodium dodecanoate, measured under the same conditions, was used as a standard for evaluating the biodegradability of these cleavable surfactants. For cleavable surfactants derived from epoxides and oxocarboxylates, the biodegradation was considerably influenced by the length of the lipophilic alkyl chain, the presence of the oxymethyl moiety in the lipophilic group, and the number of methylene units between the dioxolane ring and the carboxylate group. For another type of cleavable surfactant, 2-(long-chain alkyl)-1,3-dioxolane-4,5-dicarboxylate, the biodegradation rate for the compound, bearing a proton at position 2 in the dioxolane ring, is faster than that for the corresponding compound bearing a methyl group at position 2.     

Zwitterionic surfactants: Structure and performance

The performance and biodegradability of some zwitterionic surfactants have been compared with those of conventional anionic and nonionic surfactants. The zwitterionics are superior base materials for formulating laundry products with or without phosphates. In addition to having excellent performance properties, ammoniocarboxylates are highly biodegradable with respect to functional and ultimate degradation.     

Development and application of kinetic models for the primary biodegradation of non-ionic surfactants

The growing concern for the environment is promoting the use of surfactant products from renewable sources such as fatty alcohol ethoxylates. The high production and use of these products implies the need to develop models that enable predictions of their behaviour in biodegradation processes. The biodegradation tests were carried out according to the OECD 301 E test for ready biodegradability. In this work, kinetic models of general application to surfactant biodegradation are developed, both for substrates that do not support growth and for those that do, considering a residual substrate concentration as not being biodegraded. The models were applied to three commercial non-ionic surfactants, fatty alcohol ethoxylates with different carbon-chain lengths and degrees of ethoxylation, also analysing the initial surfactant concentration.     

Fettalkoholsulfate – Die ökologische Absicherung einer wichtigen Gruppe von Waschmitteltensiden

Fatty Alcohol Sulfates – The Ecological Evaluation of a Group of Important Detergent Surfactants The biodegradability and ecotoxicological properties of natural raw materials based fatty alcohol sulfates were extensively investigated. These surfactants displayed very fast and virtually complete biodegradation with respect to primary (MBAS) loss) as well as ultimate degradability (mineralization abd assimilation). This pertains also to the partially poorly soluble tallow alcohol sulfate as was shown by radiolabelling. In addition, complete anaerobic biodegradability was proved in a simulation test for sludge digestion. The effect concentrations determined in acute, subacute and chronic toxicity tests with bacteria, algae, daphniae and fish prove fatty alcohol sulfates to be surfactants of relatively low ecotoxicity, i. e. they are innocuous in the realistic environmental concentration range. This conclusion was supported by results obtained in models of aquatic biocenoses (microcosm, ecological system “sewage treatment plant – receiving water”). Thus, fatty alcohol sulfates can be unequivocally classified as “environmentally compatible” on the basis of the presented ecological data.     

表面活性剂降解研究进展

简述了表面活性剂对环境的影响及其降解的发展概况，着重讨论了表面活性剂的各种生物降解的研究方法和特点，降解动力学，结构与降解性能间的关系，影响降解的环境因素及直链烷基苯磺酸盐（LAS），烷基硫酸盐（AS）等几类常见表面活性剂的生物降解机理。并对近年发展起来的表面活性剂光催化降解的研究方法，降解机理及降解动力学作了简要介绍。