The effect of Na and Ca salts on MSWI bottom ash activation for reuse as a pozzolanic admixture

In this study the possibility of both chemical and combined chemical + thermal activation of municipal solid waste incinerator bottom ash was investigated. A number of chemical activators including Na₂SiO₃·9H₂O, NaOH, Na₂SO₄ and CaCl₂·2H₂O were individually added at varying concentrations to bottom ash/Portland cement mixtures having different bottom ash contents. The effect of the selected compounds was evaluated in terms of macroscopic properties including mechanical strength and composition of cementitious materials/water slurries. The results showed that Na-based activators were not capable of improving the characteristics of the cementitious products if compared to Portland cement under both normal and accelerated curing. Conversely, the use of calcium chloride at 40 °C-curing did promote the pozzolanic properties of bottom ash, leading to UCS values of 45.5 and 60.0 MPa after 10 and 20 days, respectively, as opposed to a value of 43.6 MPa obtained after 28 days for Portland cement under normal curing conditions.     

Cobalt in alluvial Egyptian soils as affected by industrial activities

ＩｎｔｒｏｄｕｃｔｉｏｎＩｎｎａｔｕｒｅＣｏｏｃｃｕｒｓｉｎｔｗｏｏｘｉｄａｔｉｏｎｓｔａｔｅｓ ,Ｃｏ2 + ａｎｄＣｏ3+ ,ａｎｄｆｏｒｍａｔｉｏｎｏｆｔｈｅｃｏｍｐｌｅｘａｎｉｏｎＣｏ(ＯＨ) - 3 ｉｓａｌｓｏｐｏｓｓｉｂｌｅ .ＤｕｒｉｎｇｗｅａｔｈｅｒｉｎｇＣｏｉｓｒｅｌａｔｉｖｅｌｙｍｏｂｉｌｅｉｎｏｘｉｄｉｚｉｎｇａｃｉｄｅｎｖｉｒｏｎｍｅｎｔ,ｂｕｔｄｕｅｔｏａｈｉｇｈｓｏｒｐｔｉｏｎｂｙＦｅａｎｄＭｎｏｘｉｄｅｓ,ａｓｗｅｌｌａｓｂｙｃｌａｙｍｉｎｅｒａｌｓ,ｔｈｉｓｍｅｔａｌｄｏｅｓｎｏｔｍ…     

切割钢渣活化过硫酸盐降解偶氮类染料酸性红73

切割钢渣是钢铁生产过程中的固体废弃物,如何有效处理和利用这些废渣具有减少环境污染、实现废物资源化的重要意义.本文选择河北邢台钢铁厂中切割钢渣为过硫酸盐(PS)活化剂,活化过硫酸盐(PS)去除水相中偶氮染料酸性红73(AR73),实验表明,25 mg·L~(-1) AR73在15 min内,其降解率为99.9%,TOC矿化率达58.6%.同时考察了钢渣投入量、PS浓度、初始pH值等影响因素对AR73降解效率的影响:随着PS浓度、钢渣投入量的增加,AR73的降解速率也逐渐增加;在pH为3～9时,AR73均可被有效去除,酸性条件更有利于AR73的去除.活性自由基猝灭实验表明,酸性红73的降解是通过自由基和非自由基两种机制实现的,且钢渣可多次回收重复利用.钢渣活化PS技术,还可有效去除蒽醌类染料(活性蓝19),其去除率为99.9%,矿化率可达92.0%;同时该技术对某印染废水(COD_(Cr)=5625 mg·L~(-1))的去除率达49.9%.本文所构建的切割钢渣活化过硫酸盐(PS)技术可应用于偶氮印染废水的处理,实现"以废治废"的目标.     

石英表面配合物与溶解动力学模型

阐述了石英表面配合物和溶解动力学机理之间的关系，指出了石英的反应性主要受负电性表面物种的控制，从而导致电解质、离子强度、pH等因素对石英溶解的催化效应．溶解达率的提高与反应活化能的降低成活化熵的增大有关。最后，介绍了在过渡态理论和表面反应模型基础上建立的石英溶解速率方程。     

Fe(Ⅱ)/K_2S_2O_8对水体中As(Ⅲ)的氧化研究

研究了Fe(Ⅱ)/K2S2O8对水体中As(Ⅲ)的氧化作用,以及pH值、Fe(Ⅱ)初始浓度等因素对氧化As(Ⅲ)的影响,并且采用分子探针法的竞争性实验鉴定了体系中产生的活性中间体,探讨了K2S2O8在Fe(Ⅱ)存在的条件下对As(Ⅲ)的氧化机理。     

活化赤泥吸附除磷及其机理的研究

以铝矿工业赤泥为原材料,采用酸活化、焙烧活化、热酸活化方法进行活化处理,得到除磷吸附剂,考察了pH值、反应时间和磷初始浓度等因素对除磷吸附剂吸附效果的影响.结果表明,活化赤泥具有较好的除磷能力,酸活化赤泥和焙烧活化赤泥对磷的饱和吸附量分别为155.2、144.2 mg·g-1.热酸活化赤泥除磷能力更强,其对磷的饱和吸附量可达202.9 mg·g～,经过热酸活化后的赤泥即使在pH值波动较大时也能很好处理高浓度含磷废水.溶液pH显著影响磷去除效果,在pH为7时得到最大去除量.     

Kinetics of selective catalytic reduction of NO by NH3 on Fe-Mo/ZSM-5 catalyst

The catalyst of Fe-Mo/ZSM-5 has been found to be more active than Fe-ZSM-5 and Mo/ZSM-5 separately for selective catalytic reduction (SCR) of nitric oxide (NO) with NH3. The kinetics of the SCR reaction in the presence of O2 was studied in this work. The results show that the observed reaction orders were 0.74-0.99, 0.01-0.13, and 0 for NO, O2 and NH3, respectively, at 350-450℃. And the apparent activation energy of the SCR was 65 kJ/mol on the Fe-Mo/ZSM-5 catalyst. The SCR mechanism was also deduced. Adsorbed NO species can react directly with adsorbed ammonia species on the active sites to form N2 and H2O. Gaseous O2 might serve as a reoxidizing agent for the active sites that have undergone reduction in the SCR process. It is also important to note that a certain amount of NO was decomposed directly over the Fe-Mo/ZSM-5 catalyst in the absence of NH3.     

Neutron activation method in the analysis of environmental objects

ＮｅｕｔｒｏｎａｃｔｉｖａｔｉｏｎｍｅｔｈｏｄｉｎｔｈｅａｎａｌｙｓｉｓｏｆｅｎｖｉｒｏｎｍｅｎｔａｌｏｂｊｅｃｔｓＧ．Ｍ．Ｋｏｌｅｓｏｖ（Ｖ．Ｉ．ＶｅｒｎａｄｓｋｙＩｎｓｔｉｔｕｔｅｏｆＧｅｏｃｈｅｍ。＆Ａｎａｌ．Ｃｈｅｍ．，ＲｕｓｓｉａｎＡｃａｄ...     

Determination of toxic elements in waters and sediments from River Subin in the Ashanti Region of Ghana

Waters and sediments of Subin River, which flows through the industrial and commercial areas of Kumasi in the Ashanti region of Ghana, were geochemically investigated to ascertain heavy metal pollution levels due to anthropogenic activities. The study shows preoccupying pollution levels that constitute a threat to public and ecological systems. The waters of Subin River are neutral to slightly basic, inferred from pH values of 6.89–7.65). Electric conductivity (EC) of the waters ranges from 822 to 1,821 μs/cm and the range of total dissolved solids (TDS) is from 409 to 913 mg/l. Toxic elements contents of sediments and waters from 10 sites along the river were analysed by instrumental neutron activation analysis (INAA), and Al, As, Cd, Cr, Cu and Zn were determined. The concentrations of Al, As, Cd, Cr, Cu and Zn in the waters range between 4.02–15.18, 0.007–0.16, 0.002–0.05, 0.001–0.019, 1.32–7.04 and 4.28–10.2 mg/l, respectively. The contamination factors (CF) computed for the elements indicate that with the exception of sampling site S10, the sediments are polluted with Cd. Chromium contamination in the sediments is observed at S6 and S7, where the CF values were 1.39 and 1.52, respectively. The pollution load indices (PLI) were low (<1) and ranged from 0.14 to 0.75, suggesting that the overall sediment column of the river is not polluted.     

沈阳市区大气颗粒物元素组分及其分布

本研究采用美国安德逊五段冲击式采样器进行大气颗粒物采样，用中子活化法进行分析，获得４３种元素质量浓度，并求得各种元素的质量中值直径和几何标准差。