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991.
研究了NDA-66新型超高交联树脂对邻苯二甲酸的吸附及脱附性能。实验结果表明:静态吸附过程中,在初始邻苯二甲酸质量浓度1 000 mg/L、溶液pH=2.0、吸附时间600 min的条件下,吸附量可达190 mg/g;动态吸附过程中,处理11吸附床层体积倍数(BV)的邻苯二甲酸溶液,当溶液流量为1.5 BV/h时,吸附率可达100%;动态脱附过程中,在w(NaOH)= 6%、脱附温度328 K的最佳脱附条件下,脱附率可达99%以上。  相似文献   
992.
The goal of this work was to propose a novel method for the solid-phase extraction of the herbicides diquat (DQT2+) and difenzoquat (DFQT+) from aqueous medium using polymeric Amberlite XAD-2 and XAD-4 resins in the presence of sodium dodecylsulfate (SDS). The addition of SDS to the medium was of fundamental importance in order to allow the formation of a negatively charged surface able to sorb the cationic solutes. Several factors that could influence the sorption process, such as SDS concentration in the medium, sorbent mass, pH, ionic strength, and initial concentration of the solutes were investigated. Kinetic studies were also performed to model the system and to identify the mechanisms that operate the sorption process of the herbicides. SDS concentration in the medium presented remarkable influence on the extraction efficiency, achieving maximum values when the ratios [SDS]/[herbicide] were approximately 90, for XAD-2, and 22 and 11 for DQT2+ and DFQT+, respectively, for XAD-4. The sorption process followed a pseudo second-order kinetic in all cases studied. It was also found that an intraparticle diffusion process controlled exclusively the sorption of the herbicides by the Amberlite XAD-2 and XAD-4 resins in the first 15 min, becoming less active with time.  相似文献   
993.
Phosphate fertilizers and herbicides such as glyphosate and MCPA are commonly applied to agricultural land, and antibiotics such as tetracycline have been detected in soils following the application of livestock manures and biosolids to agricultural land. Utilizing a range of batch equilibrium experiments, this research examined the competitive sorption interactions of these chemicals in soil. Soil samples (0-15 cm) collected from long-term experimental plots contained Olsen P concentrations in the typical (13 to 20 mg kg?1) and elevated (81 to 99 mg kg?1) range of build-up phosphate in agricultural soils. The elevated Olsen P concentrations in field soils significantly reduced glyphosate sorption up to 50%, but had no significant impact on MCPA and tetracycline sorption. Fresh phosphate additions in the laboratory, introduced to soil prior to, or at the same time with the other chemical applications, had a greater impact on reducing glyphosate sorption (up to 45%) than on reducing tetracycline (up to 13%) and MCPA (up to 8%) sorption. The impact of fresh phosphate additions on the desorption of these three chemicals was also statistically significant, but numerically very small namely < 1% for glyphosate and tetracycline and 3% for MCPA. The presence of MCPA significantly reduced sorption and increased desorption of glyphosate, but only when MCPA was present at concentrations much greater than environmentally relevant and there was no phosphate added to the MCPA solution. Tetracycline addition had no significant effect on glyphosate sorption and desorption in soil. For the four chemicals studied, we conclude that when mixtures of phosphate, herbicides and antibiotics are present in soil, the greatest influence of their competitive interactions is phosphate decreasing glyphosate sorption and the presence of phosphate in solution lessens the potential impact of MCPA on glyphosate sorption. The presence of chemical mixtures in soil solution has an overall greater impact on the sorption than desorption of individual organic chemicals in soil.  相似文献   
994.
炭化紫茎泽兰吸附生活污水中的有机物   总被引:1,自引:0,他引:1  
紫茎泽兰目前已被列入我国首批外来入侵物种,排在第一位。为达到有效防控紫茎泽兰扩散的目的,对紫茎泽兰进行资源化利用是相对较佳的途径。通过对紫茎泽兰炭化处理后用于处理生活污水中的有机物,实现以害制废。采用等温吸附实验研究了炭化紫茎泽兰用作吸附剂吸附生活污水中有机物的吸附特性,并讨论了炭化紫茎泽兰吸附生活污水中COD的初始浓度、吸附时间、吸附温度、吸附剂投加量等影响因素。结果表明,当炭化紫茎泽兰的投加量为0.05 g,吸附接触时间为2 h,吸附温度为20℃,180 r/min,生活污水中进水COD浓度大于1 000 mg/L时,去除率可达62.9%。采用Langmuir、Freundlich吸附等温式对吸附平衡数据进行了拟合,结果表明吸附等温线符合Freundlich模型。  相似文献   
995.
To counteract global species decline, modern biodiversity conservation engages in large projects, spends billions of dollars, and includes many organizations working simultaneously within regions. To add to this complexity, the conservation sector has hierarchical structure, where conservation actions are often outsourced by funders (foundations, government, etc.) to local organizations that work on‐the‐ground. In contrast, conservation science usually assumes that a single organization makes resource allocation decisions. This discrepancy calls for theory to understand how the expected biodiversity outcomes change when interactions between organizations are accounted for. Here, we used a game theoretic model to explore how biodiversity outcomes are affected by vertical and horizontal interactions between 3 conservation organizations: a funder that outsourced its actions and 2 local conservation organizations that work on‐the‐ground. Interactions between the organizations changed the spending decisions made by individual organizations, and thereby the magnitude and direction of the conservation benefits. We showed that funders would struggle to incentivize recipient organizations with set priorities to perform desired actions, even when they control substantial amounts of the funding and employ common contracting approaches to enhance outcomes. Instead, biodiversity outcomes depended on priority alignment across the organizations. Conservation outcomes for the funder were improved by strategic interactions when organizational priorities were well aligned, but decreased when priorities were misaligned. Meanwhile, local organizations had improved outcomes regardless of alignment due to additional funding in the system. Given that conservation often involves the aggregate actions of multiple organizations with different objectives, strategic interactions between organizations need to be considered if we are to predict possible outcomes of conservation programs or costs of achieving conservation targets.  相似文献   
996.
恰到好处的奖罚制度是促成企业自觉环保或者监管机构积极监理的前提。特别地,为促成企业自觉地采取环保行动,必须加大针对监管机构不作为的惩戒力度,而不仅仅是进一步地提高针对企业环保行为的奖罚力度。这就给环境监管机构带来了莫大的压力。因此,为有效缓解监管机构的工作压力,有必要建立节能减排达标申报制度。基于节能减排达标申报制度的信号博弈分析,排放达标企业将如实申报自己的节能减排情况。但只要监管机构对于申报排放达标企业意思表示真实的信心足够高,排放未达标的企业就有动机虚假申报其节能减排的情况。因此,节能减排达标申报制度存在四种可能的运行状况,亦即存在四种可能的后继博弈精炼Bayes Nash均衡策略。其中的两个为分离均衡状态,另外两个则为混同于申报达标的均衡状态。两个混同均衡的效果极差,实际上意味着节能减排达标申报制度失效。只有在分离均衡1或2下,节能减排达标申报制度的运行才较为理想。而且分离均衡2的效果要优于分离均衡1。因此,建议完善现行的排污申报与登记制度,建立节能减排达标申报制度。并尽可能地加大针对达标企业的财政补贴力度以及针对未达标企业的惩罚力度,以便尽可能地降低节能减排达标企业错误申报的可能性。与此同时,还要严格政府监管机构的组织纪律,除了要求全面核查申报达标的企业,并加大针对政府监管机构不作为的惩戒力度之外,还应经由全面核查,对节能减排达标企业的环保工作评定等级,以便重奖优者。  相似文献   
997.
The cupuassu shell (Theobroma grandiflorum) which is a food residue was used in its natural form as biosorbent for the removal of C.I. Reactive Red 194 and C.I. Direct Blue 53 dyes from aqueous solutions. This biosorbent was characterized by infrared spectroscopy, scanning electron microscopy, and nitrogen adsorption/desorption curves. The effects of pH, biosorbent dosage and shaking time on biosorption capacities were studied. In acidic pH region (pH 2.0) the biosorption of the dyes were favorable. The contact time required to obtain the equilibrium was 8 and 18 h at 298 K, for Reactive Red 194 and Direct Blue 53, respectively. The Avrami fractionary-order kinetic model provided the best fit to experimental data compared with pseudo-first-order, pseudo-second-order and chemisorption kinetic adsorption models. The equilibrium data were fitted to Langmuir, Freundlich, Sips and Radke-Prausnitz isotherm models. For both dyes the equilibrium data were best fitted to the Sips isotherm model.  相似文献   
998.
羟基磷灰石对棕壤和红壤铜吸附的影响   总被引:1,自引:0,他引:1  
采用等温平衡法,观测了羟基磷灰石对红壤、棕壤铜吸附量的影响,并应用Freundlich方程Cs=KfCen分析了土壤铜的吸附特征。结果表明,棕壤对铜的吸附能力明显高于红壤。以n(磷)∶n(铜)=1∶1向棕壤与红壤中施用羟基磷灰石,会增加两种土壤对铜的吸附量。其中,羟基磷灰石影响红壤对铜吸附能力明显高于棕壤。增加羟基磷灰石的施用量,会增加红壤与棕壤对铜的吸附量,提高土壤铜的吸附能力。高量羟基磷灰石[n(磷)∶n(铜)=4∶1]的作用效果最为明显;与对照相比,铜的吸附量分别增加62.1%和28.4%。据此推测,在铜污染红壤或棕壤上,可以选用羟基磷灰石作为磷肥的肥源。  相似文献   
999.
研究了实验室自制的纳米零价铁在不同投加量、初始浓度、pH及温度条件下,对芴溶液的吸附效果、吸附等温线及吸附动力学.结果表明,随着纳米铁投加量的增加,芴的去除率升高;增加芴的初始浓度,去除率则相应下降,同时平衡吸附量增加.另一方面,纳米铁对芴的吸附能力随pH的升高而下降;温度为15~35℃时,芴的平衡吸附量随温度的升高而增加,但变化不大.纳米铁对芴的吸附等温线符合Langmuir和Freundlich方程;纳米铁对芴的吸附过程很好地符合准二级速率方程,吸附速率随芴初始浓度的增大而减小,平衡吸附量随芴初始浓度的增大而增大.除上述结果以外,本文还对此反应体系的吸附机理进行了初步探讨.  相似文献   
1000.
铀在凹凸棒石上的吸附特性与机制研究   总被引:2,自引:2,他引:0  
刘娟  陈迪云  张静  宋刚  罗定贵 《环境科学》2012,33(8):2889-2894
采用静态实验方法研究了凹凸棒石对水溶液中铀的吸附特性,考察了溶液pH值、初始浓度、吸附时间对吸附的影响,用扫描电镜(SEM)、X射线衍射仪(XRD)表征凹凸棒石的形貌和结构,用傅里叶变换红外光谱仪(FTIR)表征凹凸棒石吸附铀前后结构的变化,探讨了凹凸棒石对铀的吸附动力学及吸附机制.结果表明,pH值对凹凸棒石吸附铀的影响显著,且在pH=5时吸附量最大.吸附量随着时间增大而增大,在2 h内可以达到平衡,吸附等温线方程符合Langmuir等温吸附模型,吸附过程为准二级动力学模型.由FTIR分析可得,凹凸棒石吸附铀后,在高频区3 700~3 000 cm-1内吸光度减弱,可能是由于铀与凹凸棒石的R—OH发生配位作用形成了R—OUO2+或(R—O)2UO2等络合物;在中频区1 700~800 cm-1内吸光度减弱,可能是铀离子和镁离子产生离子交换作用.铀在凹凸棒石上的吸附机制主要表现为离子交换和配位作用.  相似文献   
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