Multivariate Statistics of the Pyrolysis Products of High Molecular Components in Pulping Wastewaters to Explain Their Toxicity (6 pp)

Background, Aim and Scope At present, large-scale paper manufacture involves delignification and bleaching by elemental chlorine free (ECF) or totally chlorine free (TCF) processes. The wastewater is purified by secondary treatment (mechanical, chemical and biological) which removes most of the toxic substances from the discharge. However, we found residual toxicity in the high molecular (> 1000 D) matter (HMWM) of the discharge by test of the RET (reverse electronic transfer) inhibition. This fraction consists mainly of polydisperse lignin (LIG) and carbohydrate (CH) macromolecules. Structural units in these molecules are studied by pyrolysis gas chromatography / mass spectrometry (Pyr-GC/MS). In the present work, our aim was to find out those structural units which could explain the RET toxicity of LIG or CH molecules. We compared statistically RET toxicity values of the HMWM samples from treated wastewaters of pilot pulping experiments and intensity variation of the pyrolysis product gas chromatograms of these samples. This application is a novel study procedure. Methods Pyrolysis products (Py-GC/MS results) and inhibition of RET (reverse electronic transport toxicity) as TU50 and TU20 of HMWM (High Molecular Weight Material; Mw > 1000 D) were compared by multivariate statistics. The samples were from laboratory pilot stages of TCF (Totally Chlorine Free) and ECF (Elemental Chlorine Free) manufacture of softwood pulp. Py-GC/MS was done without and with addition of TMAH (Tetra Methyl Ammonium Hydroxide). The name and structure of each abundant fragment compound was identified from its retention time and mass spectrum compared to authentic reference compounds or literature. Four sets of Toxicity Units (TUs) and GC peak areas of the pyrolysis fragments were obtained. The data were normalized by division with LIG (lignin content of each sample). TU values were dependent and the fragment values independent (explanatory) variables in statistical treatments by SPSS system. Separate analyses of correlations, principal components (PCA) and stepwise multiple linear regression (SMLR) were performed from the four sample sets TCF and ECF with and without TMAH. Results and Discussion From the CH fragments, 2-furfural in TCF, and from the LIG fragments, styrene in ECF showed the highest probabilities to originate from source structures of toxicity. Other possible compounds in concern were indicated to be CH fragment 2-methyl-2-cyclopenten-1-one in ECF and LIG fragments 2-methoxy-4-methylphenol, 4,5-dimethoxy-2-methylphenol and 2-methylphenol in TCF.     

阿勒泰地区土壤微量元素环境背景值分布特征

从土壤形成的自然环境特点，成土母岩、母质等方面了区域土壤环境背景值特征，为地区土地资源的合理开发利用、农牧业合理布局、土壤污染防治等提供基础资料。     

室内空气污染概述

由于燃料燃烧、烹饪、人类活动、不合格建材和装饰材料的使用，房屋的密闭性结构等诸多因素，使室内空气污染远高于室外，从而严重地危害人们的健康，甚至导致多种疾病的发生。文章较全面地概述了室内空气污染的来源和类型，对人体的危害情况、目前的分析测试方法和标准样样品状况。     

污泥焚烧底灰中重金属残留特性的实验研究

利用原子吸收分光光度计和程序控制温升炉研究了沈阳市污水处理厂污泥在不同焚烧工况下重金属Cu、Cr、Cd、Zn、Ni和Pb在焚烧底灰中的残留特性。考察了升温速率、焚烧温度、含水率以及停留时间等因素对重金属在污泥底灰中的残留特性的影响。实验表明 ,Pb、Cd和Cu在灰渣中的残留率随着温度和停留时间的增加而降低。大部分的重金属元素Zn、Cu和Cr残留在灰渣中 ,Cd、Pb和Ni部分残留在灰渣中     

焚烧炉医疗垃圾输送装置

焚烧炉医疗垃圾输送装置是专门为医疗垃圾焚烧炉研究设计的配套上料设备.具有体积小,操作方便,实现全自动控制等优点.成功地替代了人工上料方式,有效避免了操作者与物料的直接接触.上料速度均匀可调,有利于保证和提高焚烧效率.清洗、消毒方便,符合有关规范要求.     

焚烧炉医疗垃圾输送装置

焚烧炉医疗垃圾输送装置是专门为医疗垃圾焚烧炉研究设计的配套上料设备。具有体积小，操作方便，实现全自动控制等优点。成功地替代了人工上料方式，有效避免了操作者与物料的直接接触。上料速度均匀可调，有利于保证和提高焚烧效率。清洗、消毒方便，符合有关规范要求。     

绿色高分子材料及其发展展望

介绍了环境友好的绿色高分子材料的重要性，列举了几种可降解高分子材料的类型及其特性，从可降解塑料的研制方面谈及充分、合理地利用资源，同时展望绿色高分子材料的应用前景。     

Using fugacity to predict volatile emissions from layered materials with a clay/polymer diffusion barrier

Structural insulated panels (SIPs) have significant environmental and energy advantages. However, the tight structure that results may cause degraded indoor air quality and the potential release of volatile organic compounds (VOCs) from these layered materials must be considered. A physically based model for predicting VOC emissions from multi-layer materials is described. Fugacity is used to eliminate the concentration discontinuities at the interface between layers. This avoids an obstacle associated with numerically simulating mass transfer in composite materials. The numerical model is verified for a double-layer system by comparing predicted concentrations to those obtained with a previously published analytical model. In addition, hexanal emissions from multi-layer SIPs are simulated to demonstrate the usefulness of the fugacity approach. Finally, the multi-layer model is used to investigate the impact that clay/polyurethane nanocomposite diffusion barriers can have on VOC emissions. Indoor gas-phase concentrations can be greatly reduced with a barrier layer on the surface, thereby minimizing the environmental impact of SIPs.     

硅微粉的循环利用

硅微粉是在矿热电炉内生产含硅量在75％以上的硅铁合金和工业硅时，产生大量挥发性很强的SiO2和Si气体与空气迅速氧化并冷凝而成的。硅微粉由于具有优良的理化性能，广泛用于建筑、冶金、化工等行业。介绍了硅微粉的循环利用现状，探讨了存在的问题，展望了硅微粉循环利用的前景。     

青海省巴硬格莉沟—哇沿河多金属矿化带稳定同位素地质与成矿物质来源

通过对青海省巴硬格莉沟—哇沿河多金属成矿带大量矿石及围岩的硫、氢、氧、碳、铅等稳定同位素测试及分析 ,指出该区成矿物质主要来源于幔源物质与壳源物质的混合 ,成矿与矿带外围印支期 (局部包括少量早燕山期 )二长花岗岩及下元古界达肯大坂群大理岩、二云斜长片麻岩关系密切 ,成矿热液具有混合热液性质 ,主要为岩浆水与变质水的混合 ,并有一定量的大气降水加入。因此构造 (哇洪山断裂带及其派生构造 )、岩体 (印支及早燕山期二长花岗岩 )、地层 (达肯大坂群二云斜长片麻岩、大理岩 )“三位一体”是本区多金属找矿工作的有利部位 ,在今后的找矿勘探中应予以重视。