Fungal-modification of Natural Fibers: A Novel Method of Treating Natural Fibers for Composite Reinforcement

Growing interest in green products has provided fresh impetus to the research in the field of renewable materials. Plant fibers are not only renewable but also light in weight and low in cost. Polymer composites manufactured using them find applications in diverse fields such as automobiles, housing, and furniture. However, their hydrophilic nature and inadequate adhesion with matrix limits their use in high performance applications. In this study, a novel method for improving adhesion characteristics of natural fibers has been developed. This method is carried out by treating hemp fibers with a fungus: Ophiostoma ulmi, obtained from elm tree infected with Dutch elm disease. Treated fibers showed improved acid–base characteristics and resistance to moisture. Improved acid–base interactions between fiber and resin are expected to improve the interfacial adhesion, whereas improved moisture resistance would benefit the durability of the composites. Finally, composites were prepared using untreated/treated fibers and unsaturated polyester resin. Composites with treated fibers showed slightly better mechanical properties, which is most probably due to improved interfacial adhesion.     

A Study on Benzoylation and Graft Copolymerization of Lignocellulosic Cannabis indica Fiber

Present work deals with the surface modification of Cannabis indica fiber through benzoylation and graft copolymerization of acrylonitrile (AN) onto C. indica fibers under the influence of microwave radiations. The Benzoylation of C. indica fiber was carried out by treating raw fiber with varying concentrations of benzoyl chloride solution. Different reaction parameters for graft copolymerization, such as reaction time, initiator concentration, nitric acid concentration, pH and monomer concentration were optimized to get the maximum percentage of grafting (25.54%). A suitable mechanism to explain benzoylation and graft copolymerization has been also proposed. Raw C. indica fiber, graft copolymerized and benzoylated fibers were subjected to evaluation of some of their properties like swelling behavior, moisture absorbance and resistance towards chemicals. Cannabis indica fibers treated with 5% benzoyl chloride solution and AN graft copolymerized fibers have been found to show more resistant towards moisture, water and chemicals when compared with that of untreated fibers. Morphological, structural changes, thermal stability and crystallanity of raw, graft copolymerized and benzoylated fibers have also been studied by SEM, FTIR, TGA and XRD techniques. It has been observed that the crystallinity of fiber decreases but thermal stability increases on surface modification.     

生物法处理焦化废水评述

通过对焦化废水生物处理各种工艺的比较,认为A1－A2－O工艺是目前焦化废水处理比较好的一种工艺;采用生物膜高效反应器可提高微生物浓度并选用高效菌可提高焦化废水中COD、NH3－N去除率。总结了影响化废水CDO、NH3－N去除率的多种因素,从实际工程应用中统计提出A1－A2－O工艺处理焦化废水的处理成本不超过3．5元/t。     

天然矿物材料处理印染废水的研究进展

印染废水是目前较难处理也是急需处理的工业废水。天然矿物材料通过吸附、光催化降解等作用可有效去除印染废水中的染料分子。介绍了多孔矿物、矿物／纳米半导体复合材料以及天然半导体矿物等天然矿物材料处理印染废水的研究进展。对天然矿物材料处理印染废水的研究方向进行了展望。     

樟脑和龙脑等萜类化合物废水处理工艺

采用隔油－混凝－气浮－厌氧－好氧组合工艺处理某化工厂樟脑、龙脑等萜类化合物废水，对处理装置运行的主要影响因素进行了分析研究并对运行难点提出了解决途径。运行结果表明，该工艺对含高浓度硫酸根的萜类化合物生产废水的处理效果很好，出水COD在86mg/L以内，低于广州污水排放标准。     

Critical Loads of Acidity for Forest Soils: Tentative Modifications

We reviewed the current methods for calculatingcritical loads of acidity for forest soils. The consequencesof four sets of assumptions concerning the soil modelstructure, parameter values and the critical loads criterionwere explored by comparing the values of the averageaccumulated exceedance (AAE) calculated for Finland withdeposition values for the year 1995. The AAE index is given inthe unit of deposition and is a measure of how far a region isfrom being protected in terms of fulfilling a certaincriterion, taking into account the size of the ecosystem areas.Using a critical limit for the molar ratio of theconcentrations of base cations to aluminium in soil solutiongave the lowest average accumulated exceedance. Assumingorgano-aluminium complexes and leaching of organic anions gaveAAE = 4 eq ha^-1 a^-1, which was close to the valueobtained with the standard approach used in Finland, assuminggibbsite equilibrium and no leaching of organic anions,yielding AAE = 5 eq ha^-1 a^-1. With a critical basesaturation limit, instead of the concentrations criterion, theAAE index was 17 eq ha^-1 a^-1. The highest averageaccumulated exceedance (AAE = 25 eq ha^-1 a^-1),corresponding to the lowest critical load, was obtained whenthe effects-based criterion (critical concentration or criticalbase saturation) was substituted with one restricting thedeterioration of the neutralizing capacity of the soil, ANC _le(crit) = 0. These tests illustrate the variabilityof the critical load values for acidity that can be introducedby changing the criterion or by varying the calculation method,without, however, representing the extreme values of criticalloads that could be derived.     

酸性高浓度含氟废水处理技术

介绍了对某化工厂排放的酸性高浓度含氟废水进行处理的试验，采用石灰中和沉淀，氯化钙（或聚丙烯酰胺）二级絮凝沉淀，砂滤工艺进行处理，操作控制条件如下：pH为8－9，Ca^2 与F^-的摩尔比为3．0，聚丙烯酰胺投加量为2mg/L，沉淀时间为1h，处理工程运行后的验收监测结果表明，出水中的残氟浓度可以达到国家规定的一级排放标准，且系统运行稳定，工艺简便。     

染料废水处理工艺

采用混凝－化学氧化－生物处理组合工艺处理还原红6B、还原黄棕G和2,6－二氨基蒽醌混合染料废水,色度、COD、BOD5去除率分别达到99．7％、98．8％、97．6％。     

萘系染料中间体生产废水的治理方法

综述了萘系染料中间体生产废水的治理方法,吸附法和化学氧化法等,同时也介绍了一些特殊的处理方法和综合利用方法。     

重金属捕集沉淀剂处理含络合铜废水的工艺研究

研究了用重金属捕集沉淀剂DTCR处理含络合铜废水的工艺条件，对其处理效果与无机处理剂CaO、CaO加FeSO4进行了比较。结果表明，DTCR对废水的处理不受络合剂的影响，对铜离子的捕集效率高，处理后的废水可达标排放；同时污泥生成速度快，量少，含水率低，且稳定，不会产生二次污染。     

造纸废水处理工艺试验研究

采用UASB-A/O工艺处理难降解造纸废水.试验结果表明:在系统稳定运行阶段,UASB的HRT为24 h的条件下,平均进水COD为2 777 mg/L时,平均UASB出水COD为l 274 mg/L,平均二沉池出水COD为210mg/L,平均总COD去除率为92.4％;平均进水ρ(氨氮)为40.7 mg/L时,平均UA...     

射流自吸式生物曝气塔处理废水的研究

用射流自吸式生物曝气塔对酒精生产废水及催化剂生产废水的处理进行了试验研究。与普通活性污泥法曝气池相比,射流自吸式生产曝气塔具有处理负荷高,停留时间短,处理量大的特点,是一种新型的生物反应器。     

膜生物反应器废水处理新工艺

概述了国内外膜生物反应器的研究与应用状况；介绍了其构形与特点；分析了膜污染的成因，影响因素及防制措施；指出了今后的研究方向。     

纳米铁酸盐光催化剂的制备及其在废水处理中的应用综述

概括了纳米铁酸盐(以ZnFe2O4和BiFeO3为代表)光催化剂的制备方法;综述了其在废水处理中的应用现状;讨论了催化反应中铁酸盐的特性及工艺条件(初始反应p H、初始污染物浓度、H2O2的加入等)对有机污染物降解率的影响;介绍了光助-类Fenton氧化反应的机理;对纳米铁酸盐在废水处理应用中存在的问题进行了总结,并对今后的研究方向进行了展望。     

草甘磷废水处理技术

对经电解预处理后的草甘磷废水采用选择性生物反应器－UASB－CAAS组合工艺进行处理。试验结果表明：当进水COD为26500－30000mg/L,Cl^-为5678－7892mg/L时,处理后出水COD小于150mg/L,COD平均去除率达到99％以下,系统出水可达标排放。     

电化学法处理高盐苯酚废水的研究

对在氯盐电解质中用电化学方法处理含酚废水进行了研究，着重探讨了盐的种类与浓度、反应温度与溶液：pH、电流密度、苯酚初始浓度及阴阳极转换频率对苯酚去除率的影响。在Na2SO4的浓度为0．2mol／L，NaCl的浓度为0．1mol／L、苯酚初始质量浓度为200mg／L、电流密度为0．04A／cm^2、温度为35℃、pH为12．5、阴阳极转换频率为5min/次及反应时间为200min的条件下，苯酚的去除率为99．5％，COD去除率为5％，CIO^-把苯酚氧化成了其他有机化合物。     

Chemical Treatments of Natural Fiber for Use in Natural Fiber-Reinforced Composites: A Review

Studies on the use of natural fibers as replacement to man-made fiber in fiber-reinforced composites have increased and opened up further industrial possibilities. Natural fibers have the advantages of low density, low cost, and biodegradability. However, the main disadvantages of natural fibers in composites are the poor compatibility between fiber and matrix and the relative high moisture sorption. Therefore, chemical treatments are considered in modifying the fiber surface properties. In this paper, the different chemical modifications on natural fibers for use in natural fiber-reinforced composites are reviewed. Chemical treatments including alkali, silane, acetylation, benzoylation, acrylation, maleated coupling agents, isocyanates, permanganate and others are discussed. The chemical treatment of fiber aimed at improving the adhesion between the fiber surface and the polymer matrix may not only modify the fiber surface but also increase fiber strength. Water absorption of composites is reduced and their mechanical properties are improved.     

生物膜法A/O系统处理己内酰胺废水

采用缺氧-好氧淹没式生物膜系统处理己内酰胺废水,着重探讨了碳源对硝化、反硝化的影响.研究结果表明:缺氧池进水中可生物降解COD与NO x-N的质量比必须大于3,好氧池COD负荷应小于0.98kg/(m3.d),系统才能有效地同时脱氮和去除COD.