电解锰渣煅烧时Mn、N元素形态分布与微观结构变化

电解锰行业的发展会产生大量的电解锰渣,易导致严重的环境污染,高温煅烧已成为当前无害化处理电解锰渣的高效方法之一。为探究高温煅烧时电解锰渣中特征污染物的化学形态及物相组成,选取广西某电解锰企业经不同工艺产生的电解碳酸锰渣(EMCR)与电解二氧化锰渣(EMDR),通过其理化特性及Mn、N元素形态分布与微观结构变化分析,研究了不同温度煅烧处理对电解锰渣污染物的影响。结果表明,电解二氧化锰渣中Mn元素的可氧化态与可还原态分布均大于电解碳酸锰渣。当煅烧温度在1 000 ℃以上时,2种电解锰渣中Mn元素基本上以残渣态的形式存在,通过风险评估代码(RAC)结果可知样品处于低风险甚至无风险状态,可进行后续的处理处置。2种电解锰渣中N元素的形态随着温度的升高主要以NO形式为主。通过对煅烧过程中微观结构的变化分析可知,在800 ℃时电解碳酸锰渣中石英相(SiO₂)的衍射峰强度最佳,有利于活性发展,此时的能谱分析结果显示Fe元素占比达到了52.40%,有利于Fe的回收利用,而电解二氧化锰渣的最佳煅烧处理温度显示为1 000 ℃。该研究结果可为2种电解锰渣经煅烧处置后的资源化再利用工作提供有效的数据支撑。     

2,4-dichlorophenoxyacetic acid (2,4-D) micropollutant herbicide removing from water using granular and powdered activated carbons: a comparison applied for water treatment and health safety

Abstract

Activated carbons are well-known porous materials as an effective adsorbent used for the removal of emerging contaminants, such as herbicides, which are increasingly present in water bodies. Most water treatment plants, specially in Brazil, are unable to completely remove such contaminants by the conventional process and advanced treatment using activated carbons is required. The aim of this paper was to verify the influence of the activated carbons granulometry and specific surface area on the 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide removal efficiency using distilled-deionized water and filtered water collected from a conventional Water Treatment Plant. Commercial activated carbons samples used in this work were obtained from two different manufacturers. Activated carbons were analyzed by the specific surface area, pore size and volume distribution, nuclear magnetic resonance, infrared and x-ray spectroscopy, moisture, volatile matter and ash contents. Batch adsorption isotherms experiments were used and performed by Langmuir and Freundlich models. Granular and powdered activated carbons removed over 99% of 2,4-D in distilled water and near to 99% using filtered water. The activated carbons evaluated in this work presented high performance and played a key role in water treatment by removing 2,4-D herbicide, ensuring the protection of human health and the ecosystem.     

Development of inherent safety and health index for formulated product design

The numerous formulated products which are introduced to the market consist of chemical ingredients that may cause various safety and health hazards to the consumers. Therefore, it is extremely important to practice a systematic methodology to formulate products with acceptable safety and health performances. This work presents an index-based methodology to assess the safety and health hazards of the ingredients during the early formulation stage of product design. Hence, new inherent safety and health sub-indexes are introduced to improve the current safety and health hazards that are needed in formulated product design. The inherent safety and health sub-indexes are assigned with scores based on the degree of potential hazards. A higher score indicates a higher safety risk or severe health effect, and vice versa. The proposed methodology will greatly assist the users to identify the adverse safety and health effects caused by the ingredients. Hence, it is pivotal to eliminate or reduce the safety and health impacts from product usage. A case study on common ingredients used in the formulation of paint is presented on this study to describe the proposed method.     

苯胺降解菌的分离和特性研究

从活性污泥中分离到一株细菌ＡＮ３，能以苯胺为唯一碳源、氮源和能源生长．经鉴定为食酸丛毛胞菌（Ｃｏｍａｍｏｎａｓａｃｉｄｏｖｏｒａｎｓ）．该菌株可以在高达５０００ｍｇ／Ｌ以上的苯胺中生长．当苯胺浓度为２０００ｍｇ／Ｌ左右时，经３天培养即可全部被降解．该菌株还可以利用乙酰苯胺，但不能利用其他取代类苯胺化合物．ＡＮ３菌的生长和降解苯胺的最适温度为３０℃和ｐＨ为７０．９种金属离子对该菌的生长和苯胺的降解均有不同程度抑制作用，尤以Ａｇ＋和Ｈｇ２＋为明显．该菌与苯胺降解代谢有关酶类的测定结果表明，该菌含有的邻苯二酚－２，３加双氧酶是诱导酶．     

A new environmental chamber for evaluation of gas-phase chemical mechanisms and secondary aerosol formation

A new state-of-the-art indoor environmental chamber facility for the study of atmospheric processes leading to the formation of ozone and secondary organic aerosol (SOA) has been constructed and characterized. The chamber is designed for atmospheric chemical mechanism evaluation at low reactant concentrations under well-controlled environmental conditions. It consists of two collapsible 90 m³ FEP Teflon film reactors on pressure-controlled moveable frameworks inside a temperature-controlled enclosure flushed with purified air. Solar radiation is simulated with either a 200 kW Argon arc lamp or multiple blacklamps. Results of initial characterization experiments, all carried out at 300–305 K under dry conditions, concerning NO_x and formaldehyde offgasing, radical sources, particle loss rates, and background PM formation are described. Results of initial single organic–NO_x and simplified ambient surrogate–NO_x experiments to demonstrate the utility of the facility for mechanism evaluation under low NO_x conditions are summarized and compared with the predictions of the SAPRC-99 chemical mechanism. Overall, the results of the initial characterization and evaluation indicate that this new environmental chamber can provide high quality mechanism evaluation data for experiments with NO_x levels as low as 2 ppb, though the results indicate some problems with the gas-phase mechanism that need further study. Initial evaluation experiments for SOA formation, also carried out under dry conditions, indicate that the chamber can provide high quality secondary aerosol formation data at relatively low hydrocarbon concentrations.     

绵农小麦种子巯基蛋白酶抑制剂的纯化及性质研究

绵农11号小麦种子磨粉后的胚和麸皮，经溶液浸取和硫酸铵分级沉淀获得巯基蛋白酶抑制剂（CPI）粗品，再经木瓜蛋白酶－Sepharose4B亲和层析，DEAE－Sepharose离子交换层析和SephadexG－100分子筛层析，可获得两种CPI．通过SDS－PAGE或凝胶过滤法测得其Mr分别为18800［简称CPI（H）］和10500［简称CPI（L）］．它们在PAGE，SDS－PAGE和HPLC上均为单一蛋白带．CPI（L）和CPI（H）对木瓜白酶的抑制活性（ID50）分别为7．8×10－6mol／L和3．40×10－6mol／L．对无花果蛋白酶的抑制活性分别为9．5×10－5mol／L和5．8×10－6mol／L；CPI（H）对菠萝蛋白酶有弱抑制作用，但CPI（L）则无抑制作用；无论是CPI（L）或CPI（H）对胰蛋白酶、胰凝乳蛋白酶和胃蛋白酶均无抑制作用．CPI（H）的N－末端为Ile．CPI（H）和CPI（L）在pH2．0～11．0范围内和90℃处理5min，两种CPI的抑制活性均无变化；CPI（H）和CPI（L）对木爪蛋白酶的抑制曲线经Dixon作图法，得出CPI（H）为反竞争性抑制类型，而CPI（L）为竞争性抑制类型，其Ki值为8．32×10－6mol／L．     

高Al13纳米聚合氯化铝的结构表征及混凝效果

采用AlCl36H2O和Na2CO3制备了聚合氯化铝(PAC),并采用SO42-/Ba2+沉淀-置换法分离提纯了其中的纳米Al13形态,应用27Al-NMR和XRD等现代实验技术对其中的Al13形态进行了分析表征,27Al-NMR结果表明,分离提纯后样品中的Al13含量明显高于PAC,XRD结果表明,Al13的衍射峰出现在2q角为5~25之间;混凝烧杯实验表明,纳米级PAC较传统的混凝剂AlCl3、Al2(SO4)3和PAC具有更好的除浊、脱色效果.     

南方天然水体DOM的化学分级、变化特征及三卤甲烷生成势(THMFP)特性研究

采用XAD树脂吸附法,在春季内(3～5月)连续对南方深圳水库中的水体溶解性有机物(DOM)进行化学分级表征.结果表明,天然水体DOM的总量和单个化学分级组分含量在一个季节会发生一定的波动,但总的分布特征在季节内未发生根本变化,即憎水酸(HoA)和亲水部分(HiM)浓度始终较高,而憎水碱(HoB)、憎水中性物(HoN)、弱憎水酸(WHoA)浓度则相对较低.同时,选取代表性时间点对DOM各化学分级组分进行了消毒副产物三卤甲烷生成势(THMFP)的研究,发现三卤甲烷(THMs)的主要前驱物为憎水和弱憎水有机部分,对THMFP的贡献共占约80%.进一步研究发现,憎水中性物、憎水酸、弱憎水酸的THMs生成能力较强,总体上与紫外吸收能力基本一致;但弱憎水酸表现略有不同,其SUVA(100×UV254/DOC)值并不十分突出,但三卤甲烷生成能力却明显较高,说明DOM的紫外吸收特性不能完全作为THMFP特性的替代指标.亲水物质(HiM)的SUVA值也不高,但其THMs生成能力接近憎水酸部分,值得水处理工艺研究重点关注.     

纳米氢氧化镁改性PVDF超滤膜的制备与表征

通过相转化法制备了纳米PVDF/Mg(OH)_2共混超滤膜,研究了负载Mg(OH)_2对PVDF膜结构和性能的影响。以牛血清蛋白(BSA)为模拟污染物进行超滤试验,测试膜的纯水通量和截留率;测定膜表面和水之间的接触角,进而定量分析比较膜表面的亲水性;利用微机电子控制万能试验机测试膜的机械性能;通过扫描电镜(SEM)、原子力显微镜(AFM)、X射线衍射仪(XRD)等方法表征膜表面特征。结果表明,添加纳米Mg(OH)_2的改性膜保持了原有膜的晶型结构,证明纳米Mg(OH)_2与PVDF材料有很好的相容效果。当纳米Mg(OH)_2添加量为0.8%(质量分数)时,改性效果达到最优。此时,接触角从73.1°降至59.6°,纯水通量为333.37 L/(m~2·h),较未改性前提高了126.3%,膜的拉伸最大力为6.8 N,断裂伸长率为16.2%,较未改性膜的机械性能有明显提高,膜的抗污染性也显著提高。     

Production,engine performance,combustion, emission characteristics and economic feasibility of biodiesel from waste cooking oil: A review

The depletion of fossil fuel reserves and increasing demands for diesel are considered to be important triggers for many of the initiatives that have been taken to search for possible sources for the production of biodiesel from materials available within the country. It is possible to produce biodiesel from waste/used cooking oils (WCO) that is comparable in quality to that of fresh vegetable oil. Not only does reuse of WCO, which can otherwise harm human health, reduce the burden on the government of treating oily wastewater, disposing of the waste, and maintaining public sewers, it also significantly lowers the production cost of biodiesel. In the process of frying, oil undergoes many reactions, leading to the formation of a number of undesirable compounds, such as polymers, free fatty acids, and many other chemicals. This poses challenges in the transesterification of WCO. This article covers different techniques in the production of biodiesel from WCO. It also compares combustion, emissions, and engine performance characteristics of biodiesel from WCO as well as factors affecting biodiesel production from WCO and its economic feasibility.