Synthesis of surface sulfated BiWO with enhanced photocatalytic performance

Sulfated BiWO (SBiWO) was synthesized by an impregnation method to enhance the visible-light-driven photoactivities of BiWO (BiWO). The characterization results verified that sulfate anion mainly anchored on the catalyst surface greatly extended the visible-light-responsive range without destroying the crystal lattice. Moreover, the SBiWO-based photoactivities were evaluated with the removal of Malachite Green (MG) under UV-Vis irradiation emitted from two microwave-powered electrodeless discharge lamps (MPEDL_-2) and under visible light (λ > 420 nm). The results demonstrated that the kinetic constant was increased 2.25 times, varying from 0.1478 (BiWO) to 0.3328 min^-1 (SBiWO-1). Similar results were also obtained for the visible light-driven reaction. Furthermore, radical scavengers such as t-butanol restricted the visible-light induced degradation of MG over BiWO and SBiWO-1. This indicated that the sulfating process increased the generation of reactive oxygen species, which was further verified by molecular probe with salicylic acid. Thus, more blue-shifting at λ = 618 nm was observed over SBiWO. On the basis of the above results, the photocatalytic mechanism over the sulfated catalyst was also discussed.     

电化学方法脱除烟道气中二氧化硫的研究

运用电化学方法脱除二氧化硫是一种较为清洁的脱硫方式,本文主要研究了电化学脱硫过程中,电解溴化氢以及溴氧化二氧化硫的各种影响因素,并通过优化获得了较高的电解效率９０％和脱硫效率９０％～９５％     

处理苯胺废水的电化学研究

采用电化学法处理苯胺废水 ,系统的氧化电极以恒电位法聚合制成高导电聚苯胺并压制成颗粒填料分多级填充在塔中形成固定床式电极。实验研究了不同的电位扫描速度、苯胺浓度及温度对电化学氧化还原反应的影响。实验表明 ,采用导电聚苯胺作为处理苯胺废水的氧化电极 ,可以有效地降低电化学反应的电解电位 ,提高氧化电流和反应速度 ,它是采用铂电极处理苯胺废水消耗电能的 1/ 2 .78。     

云南近46年降水与气温变化趋势的特征分析

利用云南1961-2007年降水与气温资料进行线性趋势分析和突变检验。结果表明,近46年来云南年均降水量是趋于减少的,其中夏季降水量减少较为明显,减少率为4.5 mm/10a,且夏季降水在1971年前后发生了由多到少的突变。从降水的季节变化特征及异常值统计结果来看,云南雨季平均降水量是趋于减少的,而干季平均降水量趋于增加;从降水的地域分布来看,滇南地区降水呈缓慢减少趋势;滇中降水呈缓慢减少后略升状态;滇西北降水呈略升趋势;滇东北降水为明显下降趋势。近46年云南年平均气温是升高的,从全省气温变化的季节特征及异常值统计结果来看,春夏秋冬四季增温都明显,但冬季气温增加最为显著,增加率为0.27℃/10a,冬季平均气温在1995年出现了一次由冷到暖的突变。滇中及以东地区的气温变化增暖趋势明显,滇西地区气温也为增暖的变化趋势。     

Unravelling the effects of complexation of transition metal ions on the hydroxylation of catechol over the whole pH region

Catechol pollutants (CATPs) serving as chelating agents could coordinate with many metal ions to form various CATPs-metal complexes. Little information is available on the effects of complexation of metal ions on CATPs degradation. This work presents a systematical study of •OH-mediated degradation of catechol and catechol-metal complexes over the whole pH range in advanced oxidation processes (AOPs). Results show that the pH-dependent complexation of metal ions (Zn²⁺, Cu²⁺, Ti⁴⁺ and Fe³⁺) promotes the deprotonation of catechol under neutral and even acidic conditions. The radical adduct formation (RAF) reactions are both thermodynamically and kinetically favorable for all dissociation and complexation species, and OH/O⁻ group-containing C positions are more vulnerable to •OH attack. The kinetic results show that the complexation of the four metal ions offers a wide pH range of effectiveness for catechol degradation. At pH 7, the apparent rate constant (k_app) values for different systems follow the order of catechol+Ti⁴⁺ ≈ catechol+Zn²⁺ > catechol+Cu²⁺ > catechol+Fe³⁺ > catechol. The mechanistic and kinetic results would greatly improve our understanding of the degradation of CATPs-metal and other organics-metal complexes in AOPs. The toxicity assessment indicates that the •OH-based AOPs have the ability for decreasing the toxicity and increasing the biodegradability during the processes of catechol degradation.     

Physicochemical properties and greenhouse gas emissions of water body during the decomposition of Potamogeton crispus with different values of initial debris biomass

Environmental Science and Pollution Research - A sediment-water mesocosm experiment was set up to identify the effects of different debris biomass P. crispus decomposition on water body...