椰壳生物炭对多种重金属在广东水稻土中的吸附解吸特性影响

土壤中有毒有害重金属会造成环境污染并危害人体健康.本文基于OECD 106实验准则,采用批量平衡实验方法,研究了多种有效态重金属镉(Cd2+)、钴(Co2+)和铜(Cu2+)在广东省水稻土中的吸附解吸行为特征以及添加椰壳生物炭对吸附解吸行为的影响,并探讨了pH值、温度和添加炭含量对吸附率的影响.结果表明,3种重金属在土壤中的吸附平衡时间为25 h,解吸平衡时间为30 h,添加质量浓度5％椰壳生物炭可使土壤对3种重金属的吸附率提高11.6％ ～20.0％,重金属离子在土壤中的吸附为不可逆吸附,具有明显滞后效应,Cd2+、Co2+和Cu2+的解吸滞后系数分别为33.838、1.347和0.972.在本试验条件下,土壤溶液的pH值随椰壳生物炭含量的增加而增大,温度和含炭量对吸附率的影响呈良好的线性关系(r2>0.951).这表明,在土壤中施用椰壳生物炭能有效缓解土壤中的重金属污染.     

信息素调控质粒介导的粪肠球菌耐药基因接合转移机制研究进展

粪肠球菌是一种在自然环境中广泛存在的革兰氏阳性细菌.由于其特殊的耐药机制及高频率的耐药基因转移方式,导致了环境中耐药粪肠球菌的广泛传播,生态安全形势严峻.其中,信息素应答质粒介导的粪肠球菌耐药基因的接合转移是造成粪肠球菌耐药基因快速扩散的重要方式.本文回顾了近些年关于信息素应答质粒接合转移的研究成果,分析总结了接合转移的必要条件、正负调控信息素对接合转移的调节作用,并以携带四环素抗性的质粒pCF10为例简要探讨了接合转移相关基因、蛋白的调控机制,旨在更加全面地揭示粪肠球菌的耐药基因传播机制,为耐药细菌的基因转移机制研究提供参考.     

Sludge fermentation liquid addition attained advanced nitrogen removal in low C/N ratio municipal wastewater through short-cut nitrification-denitrification and partial anammox

• Sludge fermentation liquid addition resulted in a high NAR of 97.4%. • Extra NH₄⁺-N from SFL was removed by anammox in anoxic phase. • Nitrogen removal efficiency of 92.51% was achieved in municipal wastewater. • The novel system could efficiently treat low COD/N municipal wastewater. Biological nitrogen removal of wastewater with low COD/N ratio could be enhanced by the addition of wasted sludge fermentation liquid (SFL), but the performance is usually limited by the introducing ammonium. In this study, the process of using SFL was successfully improved by involving anammox process. Real municipal wastewater with a low C/N ratio of 2.8–3.4 was treated in a sequencing batch reactor (SBR). The SBR was operated under anaerobic-aerobic-anoxic (AOA) mode and excess SFL was added into the anoxic phase. Stable short-cut nitrification was achieved after 46d and then anammox sludge was inoculated. In the stable period, effluent total inorganic nitrogen (TIN) was less than 4.3 mg/L with removal efficiency of 92.3%. Further analysis suggests that anammox bacteria, mainly affiliated with Candidatus_Kuenenia, successfully reduced the external ammonia from the SFL and contributed approximately 28%–43% to TIN removal. Overall, this study suggests anammox could be combined with SFL addition, resulting in a stable enhanced nitrogen biological removal.     

丙烯酸柱撑类水滑石的制备及其对Cu2+的吸附性能

以Zn-Al-NO3--类水滑石为前体,采用返混沉淀法制备了丙烯酸柱撑类水滑石,将其用于吸附废水中的Cu2+.实验结果表明:当初始Cu2+质量浓度为80 mg/L、丙烯酸柱撑类水滑石加入量为40 g/L、废水pH为6、吸附时间为2.0 h时,丙烯酸柱撑类水滑石对Cu2+有较好的吸附效果,在此条件下废水中Cu2+的吸附率高达95.31％;丙烯酸柱撑类水滑石对Cu2+的吸附符合Freundlich等温吸附模型.     

不同干燥处理对城市污泥物理性质和农业利用的影响

城市污泥农用正在成为世界各国处置污泥的主要方式之一,但干燥后的污泥通常结块程度高,硬度大,较难粉碎,对污泥的后续利用产生影响.试验设置了露天、棚内浇水和棚内不浇水等三个不同的污泥干燥处理,试验结果表明,露天状态处理干燥后的污泥要明显松散,结块程度较低;露天状态处理干燥后,粒径在5～10 mm和小于5 mm的污泥颗粒含量要显著高于棚内浇水和棚内不浇水处理,且露天处理干燥后污泥中水稳性团聚体所占比例最大,小于0.001 mm的粒级(粘粒)所占比例最小,不易造成土壤板结.因此,露天处理干燥后的城市污泥对农用较为有利.     

土壤中三卤甲烷(THMs)前驱物质流出的规律

通过室内模拟淋溶实验,初步探讨了以三卤甲烷生成潜能(THMFP)为指标的土壤三卤甲烷前驱物质的流出规律.结果显示:土壤淋出液中THMFP的浓度与土壤性质特别是土壤中腐殖质含量、组成与卤代活性,模拟雨水的酸度及累积淋溶量等有关.土壤中所含腐殖质的量越大、腐殖质的卤代活性越高且溶解迁移能力越强,则淋出液中THMFP的浓度越大;酸度最低(pH3.0)的模拟雨水淋洗下,淋出液中THMFP的浓度最低;模拟雨水的pH值愈低,土壤THMFP愈易流出;本实验条件下,淋出液中THMFP的浓度随累积淋溶量的增大呈下降趋势.     

Organic oxalate as leachant and precipitant for the recovery of valuable metals from spent lithium-ion batteries

Spent lithium-ion batteries containing lots of strategic resources such as cobalt and lithium are considered as an attractive secondary resource. In this work, an environmentally compatible process based on vacuum pyrolysis, oxalate leaching and precipitation is applied to recover cobalt and lithium from spent lithium-ion batteries. Oxalate is introduced as leaching reagent meanwhile as precipitant which leaches and precipitates cobalt from LiCoO(2) and CoO directly as CoC(2)O(4)·2H(2)O with 1.0 M oxalate solution at 80°C and solid/liquid ratio of 50 g L(-1) for 120 min. The reaction efficiency of more than 98% of LiCoO(2) can be achieved and cobalt and lithium can also be separated efficiently during the hydrometallurgical process. The combined process is simple and adequate for the recovery of valuable metals from spent lithium-ion batteries.     

混凝+厌氧+好氧组合工艺处理油墨废水的工程实例

采用混凝沉淀+水解酸化池+BIOFOR滤池工艺对文具厂油墨废水进行处理,通过工程实例,对工艺流程,构筑物的设计参数,调试运行进行探讨。结果表明:对于COD较大,色度非常高的油墨废水经该工艺处理后,能达到GB8978-1996《废水综合排放标准》中一级排放标准,且该工程投资小,运行费用低;管理简单方便。     

Chemical composition of the mycelium of Daldinia eschscholtzii北大核心CSCD

To investigate the chemical composition of the fungus Daldinia eschscholtzii, the compounds were separated by silica gel, Sephadex LH-20, and preparative chromatography. Their structures were identified by spectral methods. The MTT method was applied to measure the cytotoxicity of representative components. Eleven compounds were isolated and identified as 3β-hydroxyl-6,22-dien-5α,8α-peroxynitrite (1); ergosterol-9(11)-dehydroperoxide (2); mangiferonic acid (3); ergosta-4,6,8 (14),22-tetraen-3-one (4); (+)-syringaresinol (5); 3,5,3',5'-tetramethoxy-4,4,-diphenol (6); 5-methoxycoumarin (7); 5-hydroxy-2-methyl-4H-chromen-4-one (8); (2R,4R)-3,4-dihydro-5-methoxy-2-methyl-2H-1-benzopyran-4-ol (9); 2,3-dihydro-5-methoxy-2-methylchromen-4-one (10); and 7β-caruilignan C (11), respectively. Compound 4 showed inhibitory activity against H1299, H460, HGC-27, A5491, and MNK-45, with the IC50 value of 25.2 ± 2.9, 32.3 ± 4.2, 29.2 ± 1.2, 33.9 ± 3.7, and 18.0 ± 7.0 μmol/L, respectively. © 2018 Science Press. All rights reserved.