Extraction and Characterization of Microcrystalline Cellulose from Date Palm Fibers using Successive Chemical Treatments

Journal of Polymers and the Environment - The aim of present study is to extract microcrystalline cellulose (MCC) from fruit bunch branches fibers of Algerian date palm trees (phoenix dactylifera...     

The Effect of Extraction Conditions on the Chemical Characteristics of Pectin from Opuntia ficus indica Cladode Flour

Pectin from the cladode flour of Opuntia ficus indica was extracted at different ethylenediaminetetraacetate concentrations (10 or 20 %), temperatures (40 or 80 °C), pH values (2 or 11), and times (10, 20, 30 40, 50 or 60 min). The effects of the extraction conditions on the yield, purity, and chemical composition of pectin were assessed. The highest pectin yield was observed for pectin obtained under alkaline conditions and 20 % of EDTA. However, pectin produced from alkaline extractions had a lower content of GalA than pectin produced from acid extractions. Higher temperatures favored the extraction of pectin under acid conditions, but these conditions diminished the arabinose content of pectins in a time-dependent manner. The tested extraction conditions caused only slight changes in the molecular weight of the extracted pectin as a function of time.     

A Solvent-Free Approach for Production of Films from Pectin and Fungal Biomass

Self-binding ability of the pectin molecules was used to produce pectin films using the compression molding technique, as an alternative method to the high energy-demanding and solvent-using casting technique. Moreover, incorporation of fungal biomass and its effects on the properties of the films was studied. Pectin powder plasticized with 30% glycerol was subjected to heat compression molding (120 °C, 1.33 MPa, 10 min) yielding pectin films with tensile strength and elongation at break of 15.7 MPa and 5.5%, respectively. The filamentous fungus Rhizopus oryzae was cultivated using the water-soluble nutrients obtained from citrus waste and yielded a biomass containing 31% proteins and 20% lipids. Comparatively, the same strain was cultivated in a semi-synthetic medium resulting in a biomass with higher protein (60%) and lower lipid content (10%). SEM images showed addition of biomass yielded films with less debris compared to the pectin films. Incorporation of the low protein content biomass up to 15% did not significantly reduce the mechanical strength of the pectin films. In contrast, addition of protein-rich biomass (up to 20%) enhanced the tensile strength of the films (16.1–19.3 MPa). Lastly, the fungal biomass reduced the water vapor permeability of the pectin films.     

Physical Properties and Fiber Morphology of Poly(lactic acid) Obtained from Continuous Two-Step Melt Spinning

Fibers of poly(lactic acid) (PLA) produced by two-step melt-spinning are studied. The PLA resin used contains a 98:02 ratio of l:d stereochemical centers. A range of processing conditions is explored. The cold-draw ratio is varied from 1 to 8 under conditions of constant heating. In addition, three draw ratios are studied at three different heating rates. The thermal, mechanical, and morphological properties of the resultant fibers are determined. Properties can be widely manipulated through a combination of draw ratio and draw temperature. A maximum tensile strength and modulus of 0.38 GPa and 3.2 GPa, respectively, are obtainable. Using atomic force microscopy, the fiber morphology is found to be highly fibrillar; microfibril diameters are roughly 40 nm in diameter. Very high draw ratios cause the fiber to turn from shiny and translucent to dull and white; this transition is attributed to surface crazing. Significant molecular weight loss is observed upon processing (weight-average molecular weights drops between 27% and 43%).     

麦草化学制浆造纸的清洁生产工艺

提出了有机麦草加无机化肥的麦草化肥制浆造纸清洁生产工艺,以亚硫酸无机复盐替代钠碱蒸煮麦草制浆造纸,提取黑液中木质类、腐殖酸、无机氮磷等有效成分,将其制备成可固沙保土的新型环保肥料.解决了麦草化学制浆造纸黑液的污染问题,技术经济效益和环保效益俱佳.     

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.     

化工废水排放量灰色预测新方法

对偏离灰指数律的原始时序系统，累加生成不是削弱随机波动性影响折唯一途径ＧＭ（１，１）模型也不是预测模型的最佳选择。本文介绍了一种新的生成方式－－线性生成及一种新的预测模型－－ＧＩＭ（１）。某市化工行业废水排放量的预测实例表明，本方法比ＧＭ（１，１），有着更好的预测效果。     

Extraction and Characterization of Nanocrystalline Cellulose from Doum (<Emphasis Type="Italic">Chamaerops humilis</Emphasis>) Leaves: A Potential Reinforcing Biomaterial

The aim of this investigation was to extract nanocrystalline cellulose (NCC) from Moroccan Doum fibers (Chamaerops humilis) by chemical treatment to examine their potential for use as reinforcement fibers in bionanocomposite applications. The chemical composition, morphological and structural properties of the Doum fibers was determined at different stages of chemical treatment. Morphological (transmission electron microscopy and scanning electron microscopy), structural characterization (X-ray diffraction, Fourier transformed infrared), thermal characterization (thermogravimetric analysis). The suspension electrostatic stabilization (zeta potential) of NCCs was also carried out. The results of these characterization analysis found that average size of the NCC is 220 nm in length and 11 nm in diameter, with high crystallinity index (93 %), a thermal stability comparable to that of untreated Doum fibers (degradation temperature 340 °C), which is reasonably promising for the use of these nanofibers in reinforced-polymer manufacturing, and a good stability in water suspension that it allows their utilization such as reinforcement of the water-soluble polymers to prepare the bio-nanocomposite.     

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％。     

全循环工艺治理2,4-二甲基苯胺生产中的还原废水

对铁粉还原法生产２,４－二甲基苯胺过程中产生的废水,采用蒸发为水蒸气后回用于汽提的全循环工艺,可实现零排放。对循环过程进行了水平衡、热量衡算和经济分析,证明了该工艺的可行性。     

化工废气排放量灰色预测的GPSM（1）模型

在对ＧＩＭ（１）模型研究的基础上，提出了一种化工废气排放的单变量灰色幂级数曲线预测新模型「简称（ＧＰＳＭ（１）」，并建立了辨识模型参数的优化方法。结果表明，ＧＰＳＭ（１）在有线性输出的平稳系统中，比ＧＭ（１，１）更能反映原始资料提供的信息，系统分辨率高，同态性好，预测精度理想，为环境系统的拟合、预测分析和决策开辟了新途径，从而拓宽了ＧＭ（１，１）模型在环境科学领域中的应用范围。     

Development of Cellulose from Sugarcane Bagasse and Polyacrylamide-Based Hydrogel Composites by Gamma Irradiation Technique: A Study of Controlled-Release Behavior of Urea

Journal of Polymers and the Environment - Cellulose was successfully purified from sugarcane bagasse by gamma irradiation technique. The crystallinity of cellulose was reduced by gamma irradiation....     

从锦纶6生产废水中回收己内酰胺技术的改进

采用三效蒸发－间歇蒸馏技术,从锦纶６生产装置的萃取废水中回收已内酰胺。通过对三效蒸发工艺澈听改进,降低了蒸发冷凝水中已内酰胺单体含量,使蒸发冷凝水全部回用于萃取系统,萃取废水已内酰胺单体的回收率达到９９％。     

Chemical Recovery of Useful Chemicals from Polyester (PET) Waste for Resource Conservation: A Survey of State of the Art

In this paper we present the main technologies developed over the last decades on chemical recycle of PET from a practical and economical point of view. We show details of plants used to carry out solvolitic reactions emphasising steps of purification, which are sometimes not considered when discussing chemical, recycle but which, in fact, are the key feasibility factors. The recycling or modification of PET to obtain monomers and other useful chemicals as intermediates and additives is carefully considered.     

碱性和弱酸性染料混合废水处理方法

采用“中和－氯氧化－电化学反应－催化氧化”组合工艺处理碱性、弱酸性染料混合废水,可使混合废水的ＣＯＤ由１４５６０ｍｇ／Ｌ降至２１５ｍｇ／Ｌ,色度由５０００倍降至１０倍以下。试验结果表明,不同染料废水混合后可发生沉淀效应,若组合得当,可使染普废得到很大程度的净化;ＣｌＯ２对某些染料废水具有良好的去除ＣＯＤ和脱色作用。     

解决硫酸尾气污染的两转两吸工艺流程

概述了采用两转两吸工艺流程，治理硫酸生产尾气的技术改造方案。实际运行结果表明，该工艺流程是实现将硫酸毛气二氧化硫污染消灭于生产过程中最有效途径。     

废水生化处理出水吸收SO2过程相平衡关系的确定

应用相平衡理论对吸收液－ＳＯ２体系的相平衡关系进行了系统研究,确定了吸收相平衡的数学模型,并通过试验对数学模型进行了验证,结果表明,数学模型计算值与试验实测值基本吻合。     

Chemical composition determines the bioenergy potential of food waste from pre- and post-production

Journal of Material Cycles and Waste Management - The chemical characterization of the food waste allowed to discriminate between the pre-preparation and post-preparation residues from a...     

Chemical and microbiological stability of waste sludge from paper industry intended for brick production.

Due to its chemical composition, waste sludge generated in the paper industry may be used as a raw material for brick production. Brick manufacture is limited to the warmer months of the year whereas sludge is produced continuously by different effluent treatment devices. Therefore, it has to be stored until further processing. For this reason, it is essential that it is not subject to significant chemical and microbiological decomposition during storage. In the experiment, sludge from a tissue paper mill was tested for its stability. It was stored for several weeks during winter and summer periods in a pile, 2 m in height, in an open but covered store. Different leachable organic and inorganic compounds indicating possible ongoing deterioration processes, as well as pH value, redox potential, temperature, humidity and dry matter content were evaluated weekly in water extracts of homogenized sludge samples. According to the test results, the material may be considered to be chemically and microbiologically stable as there was practically no emission of odorous and toxic compounds such as H2S, NH3 and butyric acid despite prolonged storage times and elevated environmental temperatures. All the microbial species identified in the sludge during storage belong to the typical microflora of the environment.     

泥法A／O生物脱氮工艺处理腈纶废水和炼油废水

采用泥法Ａ／Ｏ生物脱氮工艺处理腈纶废水和炼油废水,出水中ＣＯＤ〈１００ｍｇ／Ｌ,ＮＨ３－Ｎ〈１５ｍｇ／Ｌ。但进水中油〉２０ｍｇ／Ｌ,ＮＨ３－Ｎ〉７００ｍｇ／Ｌ或ＳＣＮ＾－〉７０ｍｇ／Ｌ时,将对系统产生不良影响。本文介绍了１年来的运行情况,探讨了系统受影响的原因,并提出了改进建议。