Decadal changes in a polluted bay as seen from its seaweed flora: the case of Santos Bay in Brazil

The first comprehensive seaweed flora of a Brazilian region was published by Joly in 1957, describing and illustrating 105 taxa. Twenty years later Oliveira and Berchez resurveyed the area and found only 69 taxa, with a strong reduction in the number of brown algae. In another survey, performed in 1991 at the 3 studied stations with the largest species richness, the same reduction trend was found and no brown algae were observed. This reduction in biodiversity was attributed to increased pollution. Here we present the results of a new survey made in 1998-1999. This shows the return of some species recorded in the 1950s, including 7 species of brown algae. This increase in species number is thought to be a consequence of the efforts made by the local government to reduce pollution and the building of a submarine sewage terminal.     

Comparative low lethal effects of three insecticides on demographical traits and enzyme activity of the Spodoptera exigua (Hübner)

Environmental Science and Pollution Research - Many species of devastating insect pests have acquired a high degree of resistance to insecticides in the field during the last few decades....     

A pulsed switching peroxi-coagulation process to control hydroxyl radical production and to enhance 2,4-Dichlorophenoxyacetic acid degradation

• A new pulsed switching peroxi-coagulation (PSPC) system was developed. • The EC_T for 2,4-D removal in the PSPC was lower than that in the EF. • The iron consumption for 2,4-D removal in the PSPC was lower than that in the PC. The aim of this study was to develop a new pulsed switching peroxi-coagulation system to control hydroxyl radical (?OH) production and to enhance 2,4-Dichlorophenoxyacetic acid (2,4-D) degradation. The system was constructed with a sacrifice iron anode, a Pt anode, and a gas diffusion cathode. Production of H₂O₂ and Fe²⁺ was controlled separately by time delayers with different pulsed switching frequencies. Under current densities of 5.0 mA/cm² (H₂O₂) and 0.5 mA/cm² (Fe²⁺), the ?OH production was optimized with the pulsed switching frequency of 1.0 s (H₂O₂):0.3 s (Fe²⁺) and the ratio of H₂O₂ to Fe²⁺ molar concentrations of 6.6. Under the optimal condition, 2,4-D with an initial concentration of 500 mg/L was completely removed in the system within 240 min. The energy consumption for the 2,4-D removal in the system was much lower than that in the electro-Fenton process (68±6 vs. 136±10 kWh/kg TOC). The iron consumption in the system was ~20 times as low as that in the peroxi-coagulation process (196±20 vs. 3940±400 mg/L) within 240 min. The system should be a promising peroxi-coagulation method for organic pollutants removal in wastewater.     

基于博弈论组合赋权的水工隧洞TBM施工地质适宜性评价模型

为解决水工隧洞TBM施工中的地质适宜性问题,参考国内外水工隧洞TBM施工的相关实践经验,结合《工程岩体分级标准》(GB/T 50218-2014)中对围岩分类的方法,并考虑到TBM设备的运行状态,选取岩石单轴抗压强度等10个因素作为评价指标,建立水工隧洞TBM施工地质适宜性评价指标体系;评价指标的主观权重选择层次分析法...     

移动床生物膜反应器用于苯酚废水处理的性能研究

实验应用移动床生物膜反应器处理人工配制的苯酚废水,研究了在不同的苯酚进水浓度和不同的水力停留时间时苯酚的去除效率,以及反应器对冲击负荷的承受能力.结果表明,在水力停留时间为24 h、苯酚进水浓度从200 mg·L-逐渐上升至1400 mg·L-1以及苯酚进水浓度1000 mg·L-1、水力停留时间从32 h逐渐降至16 h的条件下,苯酚均能够被完全去除.对冲击负荷,MBBR具有较强的承受能力.由荧光原位杂交技术分析可知,酵母菌和真细菌是反应器中降解苯酚的主要微生物.说明移动床生物膜工艺能够高效地用于苯酚废水处理之中.     

纳米铜膜高效快速催化还原染料废水脱色

以Cu(CH3COO)2·H2O为铜源前驱物,水合肼为还原剂,通过浸渍的方法在棉布上负载纳米铜,成功制备了纳米铜膜。利用XRD和SEM对其进行了物相和形貌的表征,以亚甲基蓝(MO)、结晶紫(CV)、甲基橙(MO)和罗丹明B(RhB)等常见的8种染料为目标污染物,评价了其催化还原染料废水的性能。结果表明:制备的纳米铜膜表面的纳米铜颗粒近似球形,平均粒径约700～800 nm,能够加快还原反应中的电子转移,达到快速使染料废水快速脱色的目的。在25 ℃,纳米铜膜的大小为4 cm×6 cm,NaBH4的浓度为0.5 mol·L-1,所建立的纳米铜膜催化体系能在12 min内使20 μmol·L-1的RhB完全脱色,在相同体系下,同浓度的MB、CV和MO的脱色时间分别只需要10 s、30 s和10 min,膜材料重复使用16次以后的脱色效果仍然在98%以上,表现出良好的催化活性和循环性。     

O3/H2O2深度处理印染废水二级出水

采用O3/H2O2高级氧化工艺深度处理印染废水二级出水,考察了不同反应条件对O3/H2O2工艺的影响,并且对污水二级出水有机物(EfOM)的性质和去除行为进行了表征分析。结果表明,在pH=9,臭氧进气流量0.2 L/min,臭氧浓度116 mg/L,反应时间100 min,H2O2投加量9.79 mmol/L时,COD和色度去除率分别为82.2%、96.9%,B/C(BOD5/COD)由初始的0.10提升到0.32。此外,三维荧光光谱(3DEEM)、相对分子质量分布(MWD)以及亲疏水性分布分析表明,处理后EfOM的荧光特性发生变化,低分子量物质大量增加,亲疏水性分布也有所改变。     

腐殖酸负载对萘和1-萘酚在生物炭上吸附动力学的影响

进入环境的生物炭对有机污染物的吸附过程受到普遍共存的溶解性有机质的影响.本研究将两种腐殖酸组分负载在以玉米秸秆为原料、不同炭化温度下(200、400、600℃)制得的生物炭上,考察极性和非极性有机污染物萘和1-萘酚在原始和腐殖酸负载生物炭上的吸附动力学,分别应用拟一级、拟二级和双室一级3种动力学模型对实验数据进行拟合.结果表明,拟二级和双室一级动力学模型均能较好地描述动力学吸附过程.腐殖酸负载对生物炭上萘和1-萘酚的吸附动力学有显著影响,使得平衡吸附量(Q_e)下降,而表观吸附速率提高.致密的芳香碳组分和纳米级孔隙主要对萘和1-萘酚在生物炭上的慢吸附单元起作用,腐殖酸负载降低了生物炭的芳香化程度和孔隙度,慢吸附对总吸附的贡献(f_slow)降低.生物炭内部有机碳的致密性降低,使得萘和1-萘酚分子容易扩散进入生物炭颗粒内部,加之表面积和孔隙度减少,缩短吸附平衡时间,两种化合物的慢吸附速率常数(k_slow)均提高.负载腐殖酸后,两种化合物的快吸附速率常数(k_fast)的变化却不同.腐殖酸负载向生物炭表面引入...