Feasible conversion of solid waste bauxite tailings into highly crystalline 4A zeolite with valuable application

Bauxite tailings are a major type of solid wastes generated in the flotation process. The waste by-products caused significant environmental impact. To lessen this hazardous effect from poisonous mine tailings, a feasible and cost-effective solution was conceived and implemented. Our approach focused on reutilization of the bauxite tailings by converting it to 4A zeolite for reuse in diverse applications. Three steps were involved in the bauxite conversion: wet-chemistry, alkali fusion, and crystallization to remove impurities and to prepare porous 4A zeolite. It was found that the cubic 4A zeolite was single phase, in high purity, with high crystallinity and well-defined structure. Importantly, the 4A zeolite displayed maximum calcium ion exchange capacity averaged at 296 mg CaCO₃/g, comparable to commercially-available zeolite (310 mg CaCO₃/g) exchange capacity. Base on the optimal synthesis condition, the reaction yield of zeolite 4A from bauxite tailings achieved to about 38.43%, hence, this study will provide a new paradigm for remediation of bauxite tailings, further mitigating the environmental and health care concerns, particularly in the mainland of PR China.     

人因可靠性分析方法

回顾了人因可靠性分析 (HRA)的发展历史 ;汇总了近几十年来的各种人因可靠性分析方法 ;详细介绍了人的失误率预测技术 (THERP)、人的认知可靠性模型 (HCR)、成功似然指数法 (SL IM)的背景、使用步骤、特性等 ;分析了 THERP+ HCR的优势 ,并给出了一个应用实例。最后 ,指出了目前 HRA方法的不足并预测了 HRA的发展趋势     

污水土地处理技术研究的最新进展

本文以地下渗滤系统、慢速渗滤系统为例 ,介绍了污水土地处理技术研究的最新进展 ,指出加速污水土地处理技术产业化的进程必将大大促进我国的环境保护与生态建设工作 ,并带来巨大的环境、经济与社会效益。     

制度创新：中国自然保护区可持续经营的根本

文章在对自然保护区可持续经营概念进行阐述的基础上,分析了影响中国自然保护区经营的若干体制与制约问题,最后提出了实现自然保护区可持续经营的制度创新的建议。     

一组表达安全创新的新概念及其关联问题

为提升安全创新能力和水平及公正评价安全成果,本文从表达安全创新的新概念创设开始,以科学学思想为指导,以元概念演绎法和双向思维法,创设了正负“元事物”“元创事物”“颠覆性元创事物”等系列新概念,将表达安全创新的“负元事物”“负元创事物”和“负颠覆性元创事物”等概念与商业和科技等颠覆性创新对等起来,并推论出正负两类“颠覆性元创事物”所涉及的重要科学问题。之后,通过正负两类“颠覆性元创事物”的比较,并以近期发生的新冠肺炎为典型案例,得到一些发展和鉴别“负颠覆性元创事物”的方法与途径。研究结果对安全科技创新发展和评价等具有重要的理论意义。     

Fate of ochratoxin a in goats

Abstract

The fate of ochratoxin A (OA) was studied in goats given a single oral dose of ³H‐OA (0.5 mg/kg). More than 90% of the radioactivity was found to be excreted in 7 days and the majority (53%) was found in feces. Thirty‐eight percent, 6% and 2.26% of the activity was found in urine, milk and serum, respectively. The radioactivity in the liver and kidney 6 hours after feeding amounted to 1.5 and 0.5% of the total dose administered, respectively. Subsequent fractionation of liver and kidney homogenates revealed that microsomes, ribosomes and post‐ribosomal supernatant fractions contained most radioactivity. Thin layer chromatographic analyses revealed two additional radioactive spots with Upvalues and fluorescent characteristics different from OA, Oα and 4‐OH‐OA. Whereas OA was found as the unaltered molecule in feces, the metabolites were primarily found in urine and milk. Less than 0.03% of free OA was found in milk during the 7‐day period.     

上海市废弃电器电子产品回收现状及分析

基于废弃电器电子产品产生量大、价值高、危害性强等特点,阐述了对它们进行回收处理的必然性。文中在调研上海市废弃电器电子产品回收量、预测其产生量的基础上,阐明了在家电以旧换新的政策下上海市废弃电器电子产品具有很高回收率以及废弃电视机的所占比例极高的特点,并分析了产生这种现象的原因。     

南京市江宁区谷里镇污水处理工程工艺设计

根据谷里镇提供的水质监测资料、处理要求及现有地形条件,选用A2/O+曝气生物滤池作为该镇污水处理工程的核心处理工艺。该镇污水处理工程的设计规模为5 000 m3/d,污水处理工程的进水水质为pH:6～9 mg/L、CODCr:300 mg/L、BOD5:150 mg/L、氨氮:30 mg/L、TN:35 mg/L、TP:3 mg/L、SS:150 mg/L、动植物油:15 mg/L,经采用A2/O+曝气生物滤池作为该镇污水处理工程的核心处理工艺治理后,预计出水可以达到《城镇污水处理厂污染物排放标准》(GB 18918-2002)中的一级A标准。     

糠醛生产企业废水处理措施

使用糠醛塔下污水循环利用装置，糠醛生产污水得到全部综合利用，不产生二次污染，节省了能源消耗，减轻了环境污染，实现了“节能减排”的目标。