砷镉在不同矿物界面的相互作用过程

重金属元素镉砷由于毒性高、活性大及危害强等特点,其土壤界面化学过程是土壤科学研究中的热点问题。虽然已有大量报道涉及镉砷的界面化学过程研究,但很少排除pH这一重要因子对研究结果的干扰。因此,本研究通过序批式反应,在排除pH干扰的条件下,定量研究了砷及镉在不同矿物界面（包括氧化铝、二氧化钛和高岭石）单独存在以及共同存在条件下的相互作用过程。研究结果表明：不同矿物界面上砷和镉的吸附动力学符合准二级动力学模型,化学吸附为其控速步骤;镉及砷的吸附效率（吸附量/比表面积）在不同矿物界面上均呈现出二氧化钛界面远高于氧化铝界面,而氧化铝界面高于高岭石界面;随着镉/砷浓度比的递增,镉的关键界面作用过程调控机制由静电吸附控制为主逐步转变为静电吸附与形成界面-砷-镉三元络合物共同作用,继而转变为形成表面沉淀控制;而随着砷/镉浓度比的递增,砷的关键界面调控机制发生从吸附控制为主向为沉淀控制为主的转变。该结果可为重金属元素在土壤矿物界面的微观化学作用过程及其调控措施研究提供借鉴。     

Removal of Dispersed Dyes from Aqueous Solution Using Activated Carbon Prepared from Olive Stones

In order to valorize olive stones and to show its potential use in the sorption of two dispersed dyes, it was transformed in activate carbon and characterized. The effects of different system variables： pH, agitation speed, temperature and initial dye concentration were studied in the batch tests. The adsorption capacity of activated carbon for the dyes removal was found to be affected by the solution＇s pH. Acidic pH was found the favour disperse dyes removal. Over 95% removal was achieved for both the dyes at pH 3. The equilibrium time for both dyes was 30 min. Both Langmuir and Freundlich isotherms could be used to describe the adsorption of the dyes. Freundlich adsorption model succeeded in fitting the adsorption isotherms of dyes on olive stones activated carbon in single-solute systems, and prediction of the competitive adsorption behavior of dyes with the Freundlich-based Sheindorf-Rebuhn-Sheintuch （SRS） model gave acceptable results.     

超声协助活性炭去除水中锑的研究

[目的]探讨在超声波作用下活性炭对锑的处理效果.[方法]利用超声波协助活性炭处理废水中的锑,研究超声温度、超声时间、吸附温度、吸附时间、pH及活性炭投加量等因素对含锑废水处理效果的影响.以火焰原子吸收光谱法测定锑含量.[结果]在超声温度为40℃,超声时间为20 min,吸附时间为60 min,pH =2,活性炭与锑的比值为1 mg Sb/g活性炭时,锑的去除率可达95.86％.[结论]超声波对活性炭处理废水中的锑离子有明显的促进作用.     

厦门市红壤对氨氮的吸附研究

[目的]为了研究土壤对氨氮的吸附特性对含氨氮废水的处理提供参考。[方法]在其他条件固定的情况下,研究pH、粒径、盐度的变化对土壤吸附的影响。[结果]红壤对氨态氮具有显著的吸附作用,并且吸附速度很快,一般在30 min就可以基本达到平衡。粒度越小,pH越大,土壤对氨氮的吸附能力也越强。[结论]该研究对氨氮污水灌溉、氨氮在土壤和地下水中迁移转化的预测有重要意义。     

稻草秸秆在环境污染治理中的应用研究

稻草秸秆由于其结构的特殊性及廉价易得的特点,被越来越多的研究者利用,用于开发新型高效的吸附剂。综述了稻草秸秆作为吸附剂在环境污染治理中的应用,介绍了对稻草秸秆常用的改性方式,阐述了稻草秸秆吸附剂在重金属离子、有机物等去除方面的研究进展,并展望了稻草秸秆作为环境污染治理吸附剂的发展方向。     

片沸石吸附南湖水COD的试验研究

[目的]研究片沸石对武汉南湖水中COD的吸附.[方法]以片沸石为吸附剂,研究沸石的吸附时间、投入量、粒径、环境pH对吸附效果的作用.[结果]片沸石对南湖水中COD有较好的吸附效果,在吸附时间为40 min、投加量为20 g/L、沸石粒度为-74 μm、pH=7时,吸附率为63％左右.吸附过程符合准二级反应动力方程和Freundlich吸附等温方程.[结论]该研究为天然沸石在污水处理中的应用提供了依据.     

Hydrolysis of cellobiose by β-glucosidase in the presence of soil minerals - Interactions at solid-liquid interfaces and effects on enzyme activity levels

Extracellular enzymatic activities in soils are essential for the cycling of organic matter. These activities take place in multiphase environments where solid phases profoundly affect biocatalytic activities. Aspergillus niger is ubiquitous in soils; its β-glucosidase plays an important role in the degradation of cellulose, and therefore in the global carbon cycle and in the turnover of soil organic matter. However, the information on the interactions of this protein with soil minerals is very limited, and even less is known about their consequences for the hydrolysis of the natural substrate cellobiose. We therefore characterised the sorptive interactions of this enzyme with the soil minerals montmorillonite, kaolinite and goethite and quantified the resulting changes in the hydrolysis rate of cellobiose. Fractions of adsorbed protein, and the resulting catalytic activity loss, were lower for montmorillonite than for kaolinite and goethite at given experimental conditions; adsorption was 9.7 ± 7.3% for montmorillonite, 70.3 ± 3.1% for kaolinite and 71.4 ± 1.8% for goethite, respectively. Adsorption of the protein to the minerals caused a total decrease in the catalytic activity of 18.8 ± 3.4% for kaolinite and 17.9 ± 4.7% for goethite whereas it was not significant for montmorillonite. The average catalytic activity lost by the pool of adsorbed molecules was 26.8% for kaolinite and 25.0% for goethite. Both the amount of adsorbed protein and the resulting loss of catalytic activity were found to be independent of the specific surface areas yet were influenced by the electrical properties of the mineral surfaces. Under the experimental conditions, montmorillonite and kaolinite are negatively charged whereas goethite is positively charged. However, because of the adsorption of phosphate anions from the buffer, a charge reversal took place at the surface of goethite. This was confirmed by zeta (ζ)-potential measurements in phosphate buffer, revealing negative values for all the tested minerals. Indeed goethite interacted with the enzyme as a negatively charged surface: the amount of adsorbed protein and the resulting catalytic activity loss were very similar to those of kaolinite. Our results show that, even if an important fraction of β-glucosidase is adsorbed to the minerals, the catalytic activity is largely retained. We suggest that this strong activity retention in presence of soil minerals results from a selective pressure on A. niger, which benefits from the activity of the adsorbed, and thus stabilized, enzyme pool.     

多胺交联纤维素树脂的合成及吸附性能(Ⅺ)——天然高分子吸附剂研究

报道了多乙烯多胺交联的纤维素树脂的合成及其对若干重金属离子的静态吸附性能和吸附机理。研究结果表明，该树脂能有效地吸附Ｃｕ２＋、Ｎｉ２＋、Ｃｏ２＋、Ｚｎ２＋、Ｐｂ２＋，其吸附量可分别达１．２８，１．２４，０．５８，０．６６和０．９９ｍｍｏｌ／ｇ。在ＨＯＡｃ－ＮａＯＡｃ缓冲溶液中可选择吸附Ｃｕ２＋、Ｎｉ２＋等离子而不吸附Ｐｂ２＋。     

太阳能制冷低温储粮应用效果初探

从降低机械压缩式制冷低温储粮能耗及运行成本的角度出发,设计、建造了一台太阳能吸附式制冷系统,并将该系统在高温季节进行了低温储粮的实仓实验。测试结果表明:在夏秋高温季节,采用太阳能制冷系统冷却粮仓上部空气隔离层,可有效降低仓温,抑制粮温回升,实现准低温储粮。经济性分析表明太阳能制冷系统用于低温储粮的运行成本明显低于压缩式制冷谷物冷却机。     

钢渣对辽宁地区水稻土壤镉素吸收的影响

硅素肥料降低重金属毒性和减少重金属在植物体内积累的研究报道尚不多见。因此,开展这一领域的研究工作,将为合理应用硅素肥料修复、利用被重金属污染的土壤提供重要的理论依据。试验通过对辽宁不同地区水稻土施加钢渣,来研究钢渣对土壤吸附镉的影响。试验结果表明:施用钢渣能够增加大石桥、辽中、抚顺地区土壤对镉的吸附能力,而对盘锦、康平、苏家屯地区吸附能力影响不大;土壤对镉的等温吸附曲线,符合Langmuir等温吸附方程和Frendlich等温吸附方程,且加入钢渣前后,最大吸附量和吸附常数在不同程度上发生变化。