Soil water residence times and solute uptake on a dolomite bedrock—preliminary results

Calcium and magnesium levels have been monitored in slope foot drainage waters on a dolomite bedrock. Both calcium and magnesium rich pulses occur. Short term dissolution experiments demonstrate high calcium levels in solution while other authors have suggested that long residence time groundwater has relatively high levels of magnesium due to calcite precipitation. Patterns of field fluctuations in Ca: Mg ratios can thus be tentatively interpreted in terms of short residence time water of high calcium content mixing with long residence time water of high magnesium content. Fluorometric dye tracing has been used to indicate the orders of magnitude of soil water residence times, suggesting that quickflow components are resident in the system for a few hours to a few days. Further work is in progress.     

Photocatalytic Activity of Combustion Synthesized Nanocrystalline CeAlO3

The photocatalytic activity of combustion synthesized nanocrystalline CeAlO₃ was determined for the degradation of four anionic and four cationic dyes. The perovskite oxide showed high‐photocatalytic activity and a complete degradation of all the dyes was possible within 2 h. The photocatalytic activity of the compound was comparable with the activity of the commercial Degussa P‐25 TiO₂ catalyst. The degradation of dyes was found to follow first order kinetics and the first order degradation rate constants were determined.     

钽钼杂多酸—碱性染料多元缔合物体系的研究

在PVA、OP或Tween-60存在下,采用平衡移动法确定了碱性染料亚甲基蓝、耐尔蓝(NB)、罗丹明B(RB)、丁基罗丹明B(BRB)、结晶紫(CV)、乙基紫(EV)与Ta的摩尔比是1:1至7:1;考察了NB(或BRB)-钽钼杂多酸缔合物的红外光谱,初步探讨了反应机理:比较了几个碱性染料-钽钼杂多酸缔合物体系的光度特性,筛选出两个摩尔吸光系数>2×10~6的分析体系,并用于合金钢和地质标样中痕量Ta的测定,方法可行。     

海洋光合细菌对五种活性染料的脱色研究

实验研究了不同条件下海洋光合细菌的混合菌种对五种活性染料的脱色效果。结果表明,海洋光合细菌耐盐性较好,对五种染料都有很好的脱色效果。温度对各类染料影响不同,但五种染料都在30~35℃时达到最佳脱色效果。菌种适应的PH值范围广,驯化后活性增强。在100mg/L的浓度下,染料X-3B对细菌生长没有明显的抑制作用。     

Degradation of Textile Dyeing Wastewater by a Modified Solar Photo‐Fenton Process Using Steel Scrap/H2O2

This experimental research deals with using steel scrap as a heterogeneous catalyst. This catalyzes the oxidation reaction of real textile dye wastewater based on a modified solar photo‐Fenton oxidation process. Morphologic analysis and mapping of the elementary composition of the steel scrap have been carried out by scanning electron microscopy. The effects of concentration of H₂O₂, the pH of the solution and the catalyst loading on the degradation of textile dye wastewater are elucidated. Kinetic studies have been performed for the decolorization of wastewater under optimum conditions. It could be concluded that the steel scrap is a potential substitute for ferrous salts as a catalyst for the solar photo‐Fenton reaction.     

Oreganum Stalks as a New Biosorbent to Remove Textile Dyes from Aqueous Solutions

In the present study, Oreganum onites L. stalks in natural and chemically modified with HNO³ and H³PO⁴ used as adsorbent for removal of both acidic and basic dyes from waters. The adsorption was studied as a function of pH and contact time by batch method. All tested biosorbents were characterized by FT‐IR, scanning electron microscopy, and measuring the pH dependence of the zeta potential. The adsorption isotherms were fitted to Langmuir isotherm. The maximum adsorption capacity of dyes was 280.73 mg g^?1 for Basic Red 18, 147.06 mg g^?1 for methylene blue and 112.36 for Acid Red 111, which is comparable to that of other lignocellulosic materials. The modification process was considerably increased the biosorption capacity of lignocellulosic material, resulting in a 56–63% increase in the biosorption capacity of basic dyes and a 125% increase in the biosorption capacity of acidic dye. The present study illustrated that the most effective factors in the adsorption of basic dye were surface charge and acidic groups on lignocellulosic biosorbents, while non‐electrostatic forces as well as electrostatic forces were also effective in the adsorption of acidic dye. In conclusion, Oreganum stalks can be considered as a very prospective adsorbent for the removal of tested basic and acidic dyes.