载银TiO2半导体催化剂降解染料水溶液的研究

以新型载银ＴｉＯ２为催化剂,采用高压汞灯为光源对染料水溶液进行光催化降解。实验结果表明：采用ＴｉＯ２催化剂使直接耐酸大红（３５ｍｇ／Ｌ）、直接耐晒翠蓝（５０ｍｇ／Ｌ）和直接黑（５０ｍｇ／Ｌ）染料溶液脱至无色的时间分别为３５ｍｉｎ、６０ｍｉｎ及６０ｍｉｎ,而采用载银ＴｉＯ２催化剂,上述染料溶液脱至无色的时间分别为２０ｍｉｎ、３０ｍｉｎ及２０ｍｉｎ。探讨了ｐＨ、光强、催化剂用量及灼烧温度等对催化降解的     

Synthesis of biodegradable PVA/cellulose polymer composites and their application in dye removal

Environmentally sustainable composite films were synthesized using polyvinyl alcohol (PVA) and cellulose. Cellulose was extracted from the Agro-waste (sugarcane bagasse) using chemical pre-treatment followed by the acid-hydrolysis process. The composites were also used for the treatment of dye (Methylene blue; MB and Crystal violet dye; CV) and it was observed that the removal capacity of PVA/C was 70% for CV and 64.5% for MB dye. The biodegradation study of these composite films was also carried out using bacterial strains isolated from the marine waters of south Bengal. The biodegradation study of these polymer composites was characterized by FTIR, SEM, XRD, TGA, swelling properties, and weight loss. The results indicated that the PVA/C polymer showed a better rate of degradation (43%) than PVA (35%). Different loading parameters like pH, temperature, and inoculum dosage were studied to assess the degradation of the composite materials. Thus, biodegradable composite films were synthesized utilizing Agro-waste and had dye removal properties.     

Mechanistic insights into the selective photocatalytic degradation of dyes over TiO2/ZSM-11

● TiO₂/ZSM-11 was prepared by a facile solid state dispersion method. ● Mechanism for photocatalytic degradation of dyes was investigated. ● Both experimental and MD simulations were conducted. ● Chemisorption instead of electrostatic interaction played a critical role. Photocatalytic degradation is a promising way to eliminate dye contaminants. In this work, a series of TiO₂/ZSM-11 (TZ) nanocomposites were prepared using a facile solid state dispersion method. Methyl orange (MO), methylene blue (MB), and rhodamine B (RhB) were intentionally chosen as target substrates in the photocatalytic degradation reactions. Compared to pristine TiO₂, negative effect was observed on MO degradation while promoted kinetics were collected on MB and RhB over TZ composites. Moreover, a much higher photocatalytic rate was interestingly achieved on RhB than MB, which indicated that a new factor has to be included other than the widely accepted electrostatic interaction mechanism to fully understand the selective photodegradation reactions. Systematic characterizations showed that TiO₂ and ZSM-11 physically mixed and maintained both the whole framework and local structure without chemical interaction. The different trends observed in surface area and the photo-absorption ability of TZ composites with reaction performance further excluded both as the promotion mechanism. Instead, adsorption energies predicted by molecular dynamics simulations suggested that differences in the adsorption strength played a critical role. This work provided a deep mechanistic understanding of the selective photocatalytic degradation of dyes reactions, which helps to rationally design highly efficient photocatalysts.     

Influence of aeration intensity on the performance of A/O-type sequencing batch MBR system treating azo dye wastewater

Among the numerous parameters affecting the membrane bioreactor (MBR) performance, the aeration intensity is one of the most important factors. In the present investigation, an anoxic/aerobic-type (A/O-type) sequencing batch MBR system, added anoxic process as a pretreatment to improve the biodegradability of azo dye wastewater, was investigated under different aeration intensities and the impact of the aeration intensity on effluent quantity, sludge properties, extracellular polymeric substances (EPS) amount generated as well as the change of permeation flux were examined. Neither lower nor higher aeration intensities could improve A/O-type sequencing batch MBR performances. The results showed 0.15 m³·h^-1 aeration intensity was promising for treatment of azo dye wastewater under the conditions examined. Under this aeration intensity, chemical oxygen demand (COD), ammonium nitrogen and color removal as well as membrane flux amounted to 97.8%, 96.5%, 98.7% and 6.21 L·m^-2·h^-1, respectively. The effluent quality, with 25.0 mg·L^-1COD, 0.84 mg·L^-1 ammonium nitrogen and 8 chroma, could directly meet the reuse standard in China. In the meantime, the sludge relative hydrophobicity, the bound EPS, soluble EPS and EPS amounts contained in the membrane fouling layer were 70.3%, 52.0 mg·g^-1VSS, 38.8 mg·g^-1VSS and 90.8 mg·g^-1VSS, respectively, which showed close relationships to both pollutant removals and membrane flux.     

酸度对染料臭氧化脱色效果及溶液毒性的影响

研究了20种染料溶液在臭氧氧化过程中吸光度的变化以及pH对氧化速率的影响,应用发光菌毒性检测法测定了活性翠兰KN-G,直接混纺大红D-GLN和酸性橙Ⅱ三种染料溶液在臭氧氧化过程中的急性毒性. 结果表明:臭氧氧化20种染料的脱色过程符合一级反应动力学,其相关系数(R2)均大于0.950 0,反应溶液的初始pH对染料的脱色率有一定的影响. 染料溶液初始浓度相同时,pH为2的酸性条件更有利于染料的降解,在前45 s,酸性溶液脱色率比中性溶液高出了6%～25%. 在臭氧氧化染料溶液的过程中,溶液接近无色时,毒性较大,但随着氧化的进行其毒性逐渐降低.      

Ag–TiO2 doped photo catalytic degradation of Procion blue H-B dye in textile washwater

The photocatalytic degradation of Procion blue H-B dye in biodegraded textile washwater has been investigated for the complete removal of color and maximum reduction of chemical oxygen demand (COD). Pseudomonas putida was utilized for obtaining biodegraded textile washwater. In this process, silver-doped TiO₂ photocatalyst was prepared and experiments were carried out to study the effects of UV and mercury lamp irradiations on COD reduction and removal of color. The thus prepared silver-doped TiO₂ catalyst was characterized by thermogravimetric and differential thermal analysis, UV-visible spectrometer, X-ray diffraction, scanning electron microscope, energy dispersive X-ray microanalysis, and BET surface area techniques. Adsorption studies were also carried out to evaluate the fitness of isotherm models. The results show that the silver-doped TiO₂ has enhanced the photodegradation of Procion blue H-B dye under UV and mercury lamp irradiations. The enhanced activity of silver-doped TiO₂ is due to the enrichment of electron–hole separation by electron trapping of silver particles.     

Removal of basic fuchsin dye from aqueous solutions using graphite oxide modified aromatic polyurethane foam material

Graphite oxide modified polyurethane foam (GO/PUF) was used for adsorption of basic fuchsin from aqueous solution and adsorption conditions were optimized to attain an efficiency of 99.5%. The adsorption isotherm was in agreement with the Langmuir model. Kinetic study followed pseudo-second order. Determination of Gibbs free energy and enthalpy change of adsorption indicated spontaneous and endothermic adsorption behavior, suggesting that the adsorbent had a potential for the removal of dyes from industrial wastewater.     

Removal of Diazo dye from aqueous phase by algae Spirogyra species

This communication presents a preliminary study conducted to investigate dye (Direct Brown 2‐Diazo) colour removal using viable algae Spirogyra species. The results indicate the ability of algae Spirogyra species to remove dye colour and found to be dependent on the contact time and biomass. Colour removal mechanism by algae Spirogyra species may be attributed to biosorption and/or bioconversion and/or biocoagulation.     

碳纳米管活化过二硫酸盐降解偶氮染料酸性橙7

采用碳纳米管（CNT）活化过二硫酸盐（PS）降解偶氮染料酸性橙7（AO7）.考察了PS浓度、CNT投加量、初始pH值、温度等反应条件对AO7降解效果的影响.结果表明,当初始pH为7、n（PS）/n（AO7）为20、CNT投加量为0.2g/L时,AO7在反应480min后可以被完全脱色去除.随着PS剂量、CNT投加量和温度的升高,AO7的去除率也逐渐增加,中性条件下最有利于AO7的去除.AO7降解反应主要发生在CNT表面,且反应活化能Ea为46.76kJ/mol.通过紫外-可见分光光谱、气相色谱-质谱（GC-MS）和TOC分析表明,AO7分子偶氮键和萘环结构断裂,生成含苯环类物质,最终矿化为CO₂和H₂O.     

响应曲面法优化油茶饼对活性红15的生物吸附特征及机理

基于“以废治废”的理念,以农林业废弃物——油茶饼为原料制备生物吸附剂,吸附去除废水中的RR15(C.I. Reactive Red 15,活性红15)染料,并采用响应曲面法中的Box-Behnken设计对油茶饼生物吸附剂吸附RR15的条件进行优化. 结果表明:pH对油茶饼生物吸附剂吸附RR15的吸附容量和去除率均有显著影响(P<0.000 1);当pH为1.0、初始ρ(RR15)为300 mg/L、吸附温度为20 ℃时,油茶饼生物吸附剂对RR15的吸附效果最佳. 相比于Langmuir和Freundlich吸附等温线模型,Temkin吸附等温线模型可以更好地描述油茶饼生物吸附剂对RR15的吸附平衡数据. 吸附温度为20 ℃时,由Langmuir吸附等温线模型计算得到的Q0(吸附剂的单层饱和吸附量)为74.63 mg/g. 动力学分析显示,油茶饼生物吸附剂对RR15的吸附过程符合准二级动力学模型(R2>0.999 7),支持了限速步骤是化学吸附的理论;内部扩散和边界层扩散都可能影响吸附速率. 热力学分析表明,该吸附过程是一个自发的放热过程. FTIR(fourier transform infrared spectroscopy,傅里叶变换红外光谱)分析发现,油茶饼生物吸附剂上羟基、胺基等官能团可能是RR15染料的主要结合位点. 研究显示,油茶饼生物吸附剂是一种具有潜力的绿色吸附剂,可以有效去除废水中的RR15染料.