碳减排问题刍议

全球气候变化对人类的生存和发展造成的负面影响已是一个不争的事实。将减少碳排放量融入可持续发展已成为全世界的共识。文章主要从宏观的角度,通过追溯国际碳减排任务的确定、减排发展机制产生的历史背景和我国碳排放现状及趋势分析,论述了国际碳减排方式对我国的机遇和挑战。     

Kinetics and mechanisms of p-nitrophenol biodegradation by Pseudomonas aeruginosa HS-D38

The kinetics and mecswithhanisms of p-nitrophenol (PNP) biodegradation by Pseudomonas aeruginosa HS-D38 were investigated. PNP could be used by HS-D38 strain as the sole carbon, nitrogen and energy sources, and PNP was mineralized at the maximum concentration of 500 mg/L within 24 h in an mineral salt medium (MSM). The analytical results indicated that the biodegradation of PNP fit the first order kinetics model. The rate constant k_PNP is 2.039 × 10⁻²/h in MSM medium, K_PNP+N is 3.603 × 10⁻²/h with the addition of ammonium chloride and K_PNP+C is 9.74 × 10⁻³/h with additional glucose. The addition of ammonium chloride increased the degradation of PNP. On the contrary, the addition of glucose inhibited and delayed the biodegradation of PNP. Chemical analysis results by thin-layer chromatography (TLC), UV-Vis spectroscopy and gas chromatography (GC) techniques suggested that PNP was converted to hydroquinone (HQ) and further degraded via 1,2,4-benzenetriol (1,2,4-BT) pathway.     

灭草松在腐殖酸上的吸附及其机理

通过吸附动力学、吸附等温线和IR，ESR技术，研究了腐殖酸对灭草松的吸附及吸附机理，并且对pH、离子强度对吸附过程的影响进行了探讨。结果表明灭草松在腐殖酸上经过大约4h的初始快速阶段，此后进入慢速吸附过程。溶液pH可能会影响腐殖酸的构型。高pH时，吸附量随溶液离子强度增加稍有增加。灭草松在腐殖酸上的吸附过程中存在氢键、电荷转移作用，疏水分配也是可能存在的机理。     

多氨基树脂的制备表征及其对水中酚类化合物的吸附机制

通过沉淀聚合法制备了三交联型的聚马来酸酐树脂(Polymaleic anhydride resin,PMAR),然后氨化接枝得到系列衍生的多氨基树脂,并采用红外光谱(FTIR)、Zeta电位、元素分析、扫描电镜(SEM)和N₂吸附/解吸(BET)等手段对其进行了表征.对系列多氨基树脂的吸附性能进行比较发现,该系列树脂对4-硝基苯酚(4-NP)的吸附能力随氨基数量的增加而增加,其中以氨基数最多的四亚甲基五胺修饰的聚马来酸酐树脂PMAR-VA吸附性能最好.在各种酚类化合物中,PMAR-VA树脂对4-NP具有较高的选择性.同时,研究了树脂投加量、溶液pH、离子强度等因素对水中4-N吸附性能的影响,并对吸附过程进行了吸附动力学模拟,发现吸附过程符合拟二级动力学模型.Langmuir等温吸附模型可以很好地描述PMAR-VA对溶液中4-NP的吸附过程,最大吸附量为77.1 mg·g^-1(pH=6.0和25 ℃).吸附热力学结果表明,4-NP在PMAR-VA上的吸附是一个自发的物理吸附过程,其吸附机制主要为静电吸引和氢键.脱附再生实验发现,0.2 mol·L^-1 NaOH溶液脱附效果最优.经5次循环再生使用,PMAR-VA树脂的吸附性能没有明显下降.     

害虫对转基因Bt作物的抗性及其管理对策

至今为止,已经有２６种植物成功地转入了Ｂｔ毒蛋白基因,它们将在防治害虫中发挥重要作用．Ｂｔ作物释放的潜在风险是害虫的抗性进化．害虫对Ｂｔ毒蛋白产生抗性的机制包括行为躲避、生理生化机制及遗传机制．抗性等位基因的初始频率和抗性的遗传稳定性等特性影响着抗性管理对策的实施和效用．抗性管理对策包括Ｂｔ作物的轮作、转入多个杀虫基因、Ｂｔ毒蛋白高剂量表达、低剂量表达和目标特异表达以及避难所策略等,它们是互为补充的．其中,“高剂量／避难所”策略受到广泛的重视．但是,这些策略来自理论数学模型和实验室数据,其有效性尚需要田间实验的检验并得到进一步的完善     

Recent advances in electrochemical decontamination of perfluorinated compounds from water: a review

● Recent advances in the electrochemical decontamination of PFAS are reviewed. ● Underlying mechanisms and impacting factors of these processes are discussed. ● Several novel couped systems and electrode materials are emphasized. ● Major knowledge gaps and research prospects on PFAS removal are identified. Per- and polyfluoroalkyl substances (PFAS) pose serious human health and environmental risks due to their persistence and toxicity. Among the available PFAS remediation options, the electrochemical approach is promising with better control. In this review, recent advances in the decontamination of PFAS from water using several state-of-the-art electrochemical strategies, including electro-oxidation, electro-adsorption, and electro-coagulation, were systematically reviewed. We aimed to elucidate their design principles, underlying working mechanisms, and the effects of operation factors (e.g., solution pH, applied voltage, and reactor configuration). The recent developments of innovative electrochemical systems and novel electrode materials were highlighted. In addition, the development of coupled processes that could overcome the shortcomings of low efficiency and high energy consumption of conventional electrochemical systems was also emphasized. This review identified several major knowledge gaps and challenges in the scalability and adaptability of efficient electrochemical systems for PFAS remediation. Materials science and system design developments are forging a path toward sustainable treatment of PFAS-contaminated water through electrochemical technologies.     

2008～2017年北京市PM2.5周期性变化特征与影响机制

利用Morlet小波方法分析北京市2008~2017年PM_2.5资料,结果表明,北京市PM_2.5浓度存在显著的日变化、周变化、以及季节和年变化周期性特征,并且秋冬季的周期性特征显著高于春夏季.结合气象资料,包括水平风速、大气边界层高度、以及大气稳定度指数等,分析PM_2.5不同周期性变化对应的主要影响机制表明：大气边界层过程是PM_2.5日变化的主要影响机制,导致PM_2.5浓度白天低、夜间高.秋冬季PM_2.5日变化幅度高于春夏季;天气过程是PM_2.5周变化的主要机制,PM_2.5浓度与天气变化过程带来的风速变化和边界层高度呈强反相关关系;PM_2.5的季节变化与大气扩散能力的季节变化密切相关,秋冬季减弱的大气扩散能力加速了PM_2.5在近地面累积,春夏季则相反.     

对建立广西生态补偿机制的探讨

广西地处生态脆弱和敏感地区,经济发展相对落后,生态环境与经济发展平衡问题亟须解决。从广西生态补偿实践来看,在取得成效的同时存在补偿资金少、补偿效率低和缺乏统一规范的管理等问题,基于这些问题提出了适合广西的生态补偿办法,为构建广西生态补偿机制建言献策。     

红树林原位生态保育系统中叶绿素a的动态变化及其影响因素

根据2012年8月对广西防城港“红树林原位生态保育系统”示范基地8月1日、8月8日、8月15日3天24小时连续水质监测资料,讨论该系统叶绿素含量的周日变化情况与其他环境因子的关系,分析水质的变化情况。     

煤矿开采对地下水资源的影响及对策

煤矿开采通常会对地下水环境产生重要影响,本文根据崔木井田地下水的赋存特征,通过分析煤矿开采过程对地下水资源的影响程度,提出了保护具有区域供水意义的洛河组含水层的控制对策。