Cathode ray tube (CRT) recycling: current capabilities in China and research progress

It is estimated that approximately 6,000,000 scrap TVs and 10,000,000 personal computers are generated each year in China. Cathode ray tubes (CRTs) from these machines consist of 85% glass (65% panel, 30% funnel and 5% neck glass). The leaded glass (funnel-24%, neck-30%) may seriously pollute the environment if it is not properly disposed of. In this paper, the past, current and future status of CRT dismantling technologies as well as the CRT glass recycling situation in China are presented and discussed. Recycling technology for waste CRTs in China is still immature. While the conventional CRT dismantling technologies have disadvantages from both economic and environmental viewpoints, some of the new and emerging treatments such as automatic optical sorting facilities that have been applied in developed countries offer advantages, and therefore should be transferred to China in the next few years to solve the CRT pre-processing problem. Meanwhile, because the demand for CRT glass closed-loop recycling is extremely limited, the authorities should take effective measures to improve CRT glass recycling rates and to facilitate a match to local conditions. Moreover, we also provide a broad review of the research developments in recycling techniques for CRT cullet. The challenge for the future is to transfer these environmentally friendly and energy-saving technologies into practice.     

铁炭微电解法降解1-丁基-3-甲基咪唑六氟磷酸盐

使用铁炭微电解法降解1-丁基-3-甲基咪唑六氟磷酸盐([BMIM]PF6),并探讨了铁炭微电解法降解[BMIM]PF6的影响因素、工艺条件及其反应动力学.结果表明,影响铁炭微电解降解[BMIM]PF6的因素按从大到小的顺序为:炭铁比、pH、反应时间;铁炭微电解降解[BMIM]PF6的最佳工艺条件是:铁粉用量3g.l-1、水样pH2.5、炭铁比2、反应时间为60—90min;在此条件下,[BMIM]PF6的去除效率可以达到90%以上且该降解反应为三级反应.     

非离子表面活性剂溶液中多环芳烃的溶解特性

采用3种典型非离子表面活性剂(Tween80、Tween20和Triton X-100),对4种典型多环芳烃萘(naphtha-lene)、菲(phenanthrene)、芴(fluorene)和芘(pyrene)进行了溶解特性研究.结果表明,非离子表面活性剂对多环芳烃具有较好的增溶效果,在浓度大于临界胶束浓度(CMC)时,多环芳烃的溶解度与表面活性剂浓度成正比例线性相关通过质量溶解率(WSR)的比较,确定3种非离子表面活性剂对多环芳烃的增溶效果为Triton X-100＞Tween80＞Tween20,与其HLB值呈负相关.在非离子表面活性剂溶液中,多环芳烃的正辛醇-水分配系数(K_ow)与其胶束-水分配系数(K_m)呈现良好的线性相关关系.     

循环流化床排烟脱硫模型

以微元分析为基础并建立数据模型,分析了床内气、液相温度的变化对液滴 蒸发和对就内传热质过程的影响以及床内气、液相温度沿床高的变化趋势,并且模拟了排烟循环流化床脱硫过程,对钙硫摩尔比Ｃａ／Ｓ,入口烟气温度Ｔｇ,雾化半径ｒ０等参数对脱硫率的影响进行了分析。并与实验结果进行了比较,在下硫比等于１．４,床内温度接近露点温度的情况下,脱硫效率可以达到９６％以上,计算结果与实验结果符合很好。     

不同类型城市人工湿地底栖动物多样性的比较研究

在常州市范围内选取具有代表性的三大人工湿地,对其底栖动物多样性情况进行春秋两季的调查研究。结果显示：软件园秋季底栖动物各项生物多样性指标均高于春季,荆川公园和五星公园则呈现春季生物多样性状况优于秋季的状况。从总体上看,底栖动物的Shannon—Wiener多样性指数软件园〉荆川公园〉五星公园;Pielou均匀度指数荆川公园〉软件园〉五星公园;BI指数表现为五星公园〉荆川公园〉软件园。此外从调查结果来看,软体动物种类数、分布密度与水体的污染程度呈反向趋势,由此推断软体动物种类丰富程度可作为评价城市人工湿地水体受污染程度的重要指标。     

Evaluation of 1,4-naphthoquinone derivatives as antibacterial agents: activity and mechanistic studies

● All 1,4-naphthoquinone hybrids exhibited significant antimicrobial activity. ● Presence of a hydroxyl group on aromatic B-ring of juglone was crucial for activity. ● Juglone can cause DNA damage by producing ROS and downregulation of RecA. ● Juglone has the potential to become a disinfectant. The diverse and large-scale application of disinfectants posed potential health risks and caused ecological damage during the 2019-nCoV pandemic, thereby increasing the demands for the development of disinfectants based on natural products, with low health risks and low aquatic toxicity. In the present study, a few natural naphthoquinones and their derivatives bearing the 1,4-naphthoquinone skeleton were synthesized, and their antibacterial activity against selected bacterial strains was evaluated. In vitro antibacterial activities of the compounds were investigated against Escherichia coli and Staphylococcus aureus. Under the minimum inhibitory concentration (MIC) of ≤ 0.125 μmol/L for juglone (1a), 5,8-dimethoxy-1,4-naphthoquinone (1f), and 7-methyl-5-acetoxy-1,4-naphthoquinone (3c), a strong antibacterial activity against S. aureus was observed. All 1,4-naphthoquinone derivatives exhibited a strong antibacterial activity, with MIC values ranging between 15.625 and 500 μmol/L and EC₅₀ values ranging between 10.56 and 248.42 μmol/L. Most of the synthesized compounds exhibited strong antibacterial activities against S. aureus. Among these compounds, juglone (1a) showed the strongest antibacterial activity. The results from mechanistic investigations indicated that juglone, a natural naphthoquinone, caused cell death by inducing reactive oxygen species production in bacterial cells, leading to DNA damage. In addition, juglone could reduce the self-repair ability of bacterial DNA by inhibiting RecA expression. In addition to having a potent antibacterial activity, juglone exhibited low cytotoxicity in cell-based investigations. In conclusion, juglone is a strong antibacterial agent with low toxicity, indicating that its application as a bactericidal agent may be associated with low health risks and aquatic toxicity.     

大亚湾水体营养盐分布特征及其生态环境效应

2019年秋季和2020年春季在大亚湾海域开展了生态环境现状调查,调查要素包括水温、盐度、pH、溶解氧、化学需氧量(COD)、溶解无机氮(DIN)、磷酸盐(DIP)、叶绿素a等。秋季DIN和DIP平均浓度分别为(5.00±3.36)、(0.31±0.56) μmol/L,春季分别为(3.12±1.97)、(0.13±0.05) μmol/L,春季DIN和DIP含量低于秋季。秋、春季DIN和DIP高值区均位于淡澳河入海口、哑铃湾和范和港湾口以及渔业养殖和港口交汇海域,且呈现自湾顶至湾口逐渐减小趋势,主要受入海径流、外海水入侵、渔业养殖、污水排放等多重因素影响。大部分海域处于贫营养化状态,仅湾顶局部海域为中度富营养化水平。春季叶绿素a平均值为(2.10±1.07) μg/L,大于秋季[(0.83±0.54) μg/L],秋、春季叶绿素a空间分布大体与营养盐相同,即湾顶高,湾中和湾口逐渐降低,秋、春季N/P平均值分别为30.52±20.09和26.68±17.70,湾顶浮游植物繁殖的主要限制因子为磷,湾口的主要限制因子为氮。     

ABR-SBR法处理草浆造纸中段废水试验研究

针对草浆造纸中段废水 ,进行了ABR、SBR及ABR SBR组合处理工艺的研究 ,结果表明 :ABR的HRT为 6h时 ,废水可生化性由 0 2— 0 2 5增加到 0 4— 0 5 ;SBR最佳HRT为 8h ,单独运行 ,COD去除率 6 5 %左右 ;ABR SBR组合工艺中SBR处理效果明显提高 ,COD去除率达 80 %左右 ,且组合工艺处理效果好 ,COD和BOD5去除率达 90 %左右 ,抗冲击负荷能力强。     

活性MgO-粉煤灰固化黄土剪切特性试验研究

黄土固化处理是解决黄土地区建筑地基变形与沉降问题的有效途径。选取活性MgO、粉煤灰和水泥3种不同类型固化剂,通过开展不固结不排水直接剪切试验,研究固化剂掺量、类型和养护龄期等因素对黄土剪切性能的影响。结果表明:活性MgO可显著提高黄土抗剪强度;随着活性MgO掺量和养护龄期增加,固化黄土黏聚力和内摩擦角先增加后减小,在6%掺量和14 d养护龄期附近达到峰值;粉煤灰掺入可有效改善活性MgO固化黄土抗剪性能,尤其对黏聚力提高效果明显,随着养护龄期和固化剂掺量增加,固化土抗剪强度不断增大;水泥固化黄土抗剪强度随水泥掺量和养护龄期呈现类似增长规律。活性MgO-粉煤灰等3种材料可提高固化黄土抗剪强度,MgO-粉煤灰效果最优,单掺活性MgO次之,二者均优于水泥。