混凝沉淀法处理含砷选矿废水

某钨矿含砷选矿废水砷含量高且砷以As(V)为主要存在形态,采用混凝沉淀法处理,详细考察了生石灰、硫酸亚铁和六水三氯化铁3种混凝剂对废水中砷的去除效果。实验结果表明,在PAM投加量40 mg/L,静沉时间60 min条件下,比较分析3种混凝剂对砷的去除效果,三氯化铁为最佳除砷混凝剂。三氯化铁最佳除砷工艺条件为:pH 7.5,三氯化铁投加量986.67 mg/L,混凝反应时间25 min,PAM投加量为40 mg/L,静沉60 min,含砷选矿废水经该工艺处理后,砷去除率可达99.14%,出水砷浓度降至0.361 mg/L,达到国家污水综合排放标准(GB8978-1996)。     

土地处理系统表层土壤中磷赋存形态及其转化过程

以在江淮地区典型经济欠发达村镇(忠庙)构建的化粪池-土地处理系统为对象,研究了土地处理系统表层土壤中磷赋存形态及其转化过程。结果表明,土地处理系统表层土壤中TP含量在149.2～159.4 mg/kg之间,且在运行实验后其含量有所增加。在磷赋存形态方面,Ca-P占TP含量的百分比最高,达到33.1%,随后依次为Ex-P、Org-P、Fe-P和Oc-P,分别为26.1%、19.6%、14.2%和7.0%;在磷活性方面,活性磷(Ex-P和Fe-P)占TP含量的百分比较大,在运行实验后由38.0%增至40.3%,可能是由于惰性磷(Oc-P、Ca-P和Org-P)转化所致,而Org-P矿化速率大于其累积速率。相关性分析表明,除Ca-P外,其他各形态磷均与土壤pH不相关,而Org-P与OM、TP、Ex-P和Ca-P均呈正相关。     

EGSB 反应器处理产氢发酵液简

以厌氧颗粒污泥为接种污泥,对厌氧颗粒污泥膨胀床（EGSB）反应器处理产氢发酵液的启动性能进行了研究。结果表明,在温度为（35±1）℃,水力停留时间（HRT）为6 h的条件下,逐渐提高进水COD,经过40 d连续运行,EGSB反应器启动成功。容积负荷达到14 kg COD/（m³·d）时,COD去除率约为80%,产气量为26.84 L/d,甲烷含量为57.9%。     

Photocatalytic mineralization of glyphosate in a small-scale plug flow simulation reactor by UV/TiO2

The present work involves the photocatalytic mineralization of glyphosate on a plug flow reactor by UV/TiO₂. The effect of catalyst loading shows an optimal value (0.4 g L^?1) which is necessary to mineralize glyphosate. The kinetic rate of glyphosate mineralization decreases with the increasing initial concentration of glyphosate, and the data can be described using the first-order model. An alkaline environment is conducive to glyphosate mineralization. The mineralization efficiency increases with elevated flow rate to 114 mL min^?1, which is followed by a decrease with a further increase in flow rate due to the reduction of the residence time. The presence of external oxidants (K₂S₂O₈, H₂O₂ and KBrO₃) and photosencitizer (humic acid) can significantly enhance glyphosate mineralization. Photocatalysis oxidation ability of the three studied oxidants decrease in the order of: S₂O₈ ^2? > BrO₃ ^? > H₂O₂. Finally, the Langmuir–Hinshelwood (L-H) model was used to rationalize the mechanisms of reactions occurring on TiO₂ surfaces and L-H model constants were also determined.     

Removal of anionic azo dye from aqueous solution via an adsorption–photosensitized regeneration process on a TiO2 surface

Textile dye effluents are typically characterized by strong color and recalcitrance, even at very low concentration. The process of enrichment of anionic azo dye on the surface of TiO₂ fibers followed by photosensitization degradation under ambient air conditions was extensively investigated. Adsorption isotherms and zeta potentials were used to describe the “dye/TiO₂ surface” interface, taking into account the effects of pH on the nature and population of the surface groups on the TiO₂ fibers. The extent of the photocatalytic degradation of dye on TiO₂ surface was determined by FTIR. N₂ adsorption isotherms and optical spectra were employed to investigate the effect of photosensitization. The adsorption of dyes on the TiO₂ surface occurs via electrostatic attraction through the formation of single- or multidentate-coordinated surface complexes. Almost complete photobleaching of the absorption band at 534 nm is achieved in ~4 h. Dye-sensitized TiO₂ fiber could absorb part of the visible light spectrum (λ?<?600 nm). Interfacial electron transfer can potentially alter the degradation efficiency. The regenerated TiO₂ fiber could be reused for subsequent decolorization without a decline in adsorption efficiency compared with freshly prepared TiO₂ samples, which may be attributed to preservation of the hierarchical pore structure and restoration of the original surface properties. In summary, we propose an efficient “adsorption–photoregeneration–reuse” process applying TiO₂ fibers for the degradation of dyes in water.     

黑龙江省入境旅游客源市场结构演变分析

运用转移—份额分析法(SSM)对2000-2009年黑龙江省入境旅游外国客源市场结构演变进行了分析.结果表明:①2000-2005年黑龙江省竞争力和增长率均较小,2005-2009年竞争力有所增强,但结构优势有所下降.②全省入境旅游客源市场结构在不断变化,将13个主要客源国分为兴旺市场、崛起市场、成熟市场和停滞市场,并提出相应的市场营销建议.     

脉冲放电等离子体同时处理地下水中Cr(VI)和阿特拉津的研究

常规地下水修复技术如物理法、化学法和生物法难以同时降解地下水中重金属-有机物复合污染.本文提出多针-板脉冲放电等离子体同时降解地下水中重金属和有机物复合污染的方法 .以Cr(VI)和阿特拉津为目标污染物,研究复合污染中Cr(VI)和阿特拉津浓度、放电电压、溶液初始pH值和地下水中存在的主要离子对Cr(VI)和阿特拉津降解效果的影响,并探究放电过程生成的活性物质对复合污染中Cr(VI)和阿特拉津降解的作用效应.结果表明,相对单一污染物,复合污染物中Cr(VI)或阿特拉津的存在能够消耗放电过程产生的·H和·OH,阻碍其复合,Cr(VI)和阿特拉津在降解过程中产生协同效应.电压为13 kV时,单独处理10 mg·L^-1的Cr(VI)和阿特拉津的降解效率分别为34.0%和51.5%,而复合污染中Cr(VI)和阿特拉津的初始浓度均为10 mg·L^-1时,降解效率分别提高到45.0%和64.1%.放电电压增加,复合污染中Cr(VI)和阿特拉津的降解效率提高,但其能量效率呈下降趋势.增加溶液初始pH值,阿特拉津的降解效率减小,而Cr(VI)的降解效率呈现先...     

藻源可溶有机质对17β-雌二醇生物降解的影响

为探究藻源可溶有机质(COM)及其生物老化过程对湖泊水体中17β-雌二醇(E2)生物降解的影响特征,通过模拟生物老化,得到5种不同生物活性的COM样品:S0(78％)>S1(67％)>S2(36％)>S3(13％)>S4(1％).结果表明,经过60h的避光培养实验,相同浓度(8mgC/L)的COM样品均提高了微生物群落...     

西太平洋台风“苏迪罗”对我国珠三角地区臭氧污染影响研究

通过资料分析和数值模拟开展了2015年8月1日—10日台风“苏迪罗”对珠三角地区臭氧（O₃）污染影响的机理研究。结果表明,2015年8月5—8日,在台风接近登陆点的过程中,台风外围天气导致了高温、高辐射和静小风等气象条件,促进了光化学反应的进行和污染物的局地积累。同时,高温、高辐射等气象条件加剧了植被源区生物源挥发性有机物（BVOCs）的排放。采用化学传输模式模拟发现,植被BVOCs对O₃污染的贡献最高可达24×10^-9。结合拉格朗日粒子扩散模式（LPDM）探索了影响珠三角地区的主导气团,发现珠三角城市地区和高BVOCs源区存在交互传输的现象。污染期间,高BVOCs源区的一次排放产物（BVOCs）和二次产物(O₃)经区域输送加剧了珠三角地区O₃的污染。此外,研究发现台风外围条件下珠三角内陆盛行的偏北风与海陆热力差异引起的海风在沿海地区辐合,造成污染物局地积累,加剧并延长了O₃污染。研究有利于加强对O₃污染机理的认识,进而更好地采取针对性措施,有助于减小O₃污染带来的危害。     

Collaborative control of fine particles and ozone required in China for health benefit

● Increased DAAO offsets 3/4 of the decrease of DAAP in 2013–2020. ● DAAO increases are mainly due to O₃ concentration increase and population aging. ● Health benefit from PM_2.5 reduction after 2017 is larger than that before 2017. ● Reducing PM_2.5 concentration by 1% results in 0.6% reduction of DAAP. ● Reducing O₃ concentration by 1% results in 2% reduction of DAAO. PM_2.5 concentration declined significantly nationwide, while O₃ concentration increased in most regions in China in 2013–2020. Recent evidences proved that peak season O₃ is related to increased death risk from non-accidental and respiratory diseases. Based on these new evidences, we estimate excess deaths associated with long-term exposure to ambient PM_2.5 and O₃ in China following the counterfactual analytic framework from Global Burden Disease. Excess deaths from non-accidental diseases associated with long-term exposure to ambient O₃ in China reaches to 579 (95% confidential interval (CI): 93, 990) thousand in 2020, which has been significantly underestimated in previous studies. In addition, the increased excess deaths associated with long-term O₃ exposure (234 (95% CI: 177, 282) thousand) in 2013–2020 offset three quarters of the avoided excess deaths (302 (95% CI: 244, 366) thousand) mainly due to PM_2.5 exposure reduction. In key regions (the North China Plain, the Yangtze River Delta and the Fen-Wei Plain), the former is even larger than the latter, particularly in 2017–2020. Health benefit of PM_2.5 concentration reduction offsets the adverse effects of population growth and aging on excess deaths attributed to PM_2.5 exposure. Increase of excess deaths associated with O₃ exposure is mainly due to the strong increase of O₃ concentration, followed by population aging. Considering the faster population aging process in the future, collaborative control, and faster reduction of PM_2.5 and O₃ are needed to reduce the associated excess deaths.