腐殖酸钠和表面活性剂对黄土中石油污染物解吸增溶作用

选用十二烷基苯磺酸钠(LAS)、十二烷基硫酸钠(SDS)和十二烷基磺酸钠(SAS)对污染的土壤进行解吸实验,研究了这3种阴离子表面活性剂和腐殖酸钠对黄土中柴油类污染物的协同增溶作用.结果表明,腐殖酸钠和3种阴离子表面活性剂对黄土中柴油的解吸均有显著增溶作用,使柴油的解吸量明显增加,柴油的去除率最高可达63%.SDS对柴油的解吸量随腐殖酸钠浓度增大呈线性增加关系;但腐殖酸钠浓度增加对 LAS和SAS的解吸曲线有突越点,超过此浓度后反而会抑制解吸作用.     

氨氮在天然沸石上的吸附及解吸

研究了氨氮浓度、温度、时间、共存阳离子等对氨氮在天然沸石上吸附的影响 ,比较了HCl及NaCl溶液对氨氮解吸的效果 ,初步探讨了沸石吸附氨氮后自然硝化的规律 .结果显示 ,随着氨氮浓度的增大或温度的升高 ,沸石吸附量上升 ,最大可达 1 1 5mg·g- 1 ;沸石吸附的初始阶段 (0— 8h) ,沸石吸附量随时间显著上升 ,此后趋于平缓 ;在不同阳离子共存的情况下 ,K 可使沸石吸附量降低 5 0 %以上 ;HCl溶液对氨氮解吸的效果好于NaCl溶液 ,解吸率最高可达到 6 0 % ;沸石吸附的氨氮在硝化细菌作用下可转化为硝氮 ,溶液中硝氮浓度 1 2 0h后可达 9mg·l- 1 ,在总氮中比率达到 2 7% .     

可溶性有机质对芘在泥炭和高岭土上吸附和解吸的影响

为掌握可溶性有机质(DOM)对憎水性有机污染物吸附和解吸行为的影响,本研究选取四环多环芳烃——芘作为目标污染物,通过批平衡实验研究了不同分子量组分DOM对芘在泥炭和高岭土上吸附和解吸的影响.结果表明,吸附和解吸数据均可以用Freundlich模型很好地拟合(R²>0.93).DOM的添加抑制了泥炭对芘的吸附,并且分子量越大的DOM产生的抑制效应越明显,主要是由于DOM与芘分子的竞争、增溶作用及泥炭表面微孔的堵塞引起的.与之相反,DOM促进了芘在高岭土上的吸附,DOM分子量越大,促进效应越强,这是由于DOM与芘分子之间通过累积吸附或共吸附增加高岭土对芘的吸附.DOM促进了芘在泥炭和高岭土上的解吸,并且促进效应随分子量的增加而增强.此外,芘在泥炭和高岭土上的解吸均存在迟滞现象,均在低浓度时表现出更明显的效应.DOM_bulk和DOM_(>14000 Da)增加了芘在泥炭上的解吸迟滞现象,但降低了其在高岭土上的解吸迟滞现象.     

模拟重金属污染土壤的强化解吸与解吸液降解

文章对EDTA强化解吸模拟重金属污染土壤进行了实验研究。结果表明,EDTA能够迅速地解吸模拟土壤中的Cu、Cd和Pb等重金属。初始EDTA浓度、解吸时间以及离子强度的增加对土壤中重金属的解吸效果有一定的正影响作用。此外,考察了土壤解吸废液在零价铁/曝气体系中的处理。经过零价铁/曝气技术后,解吸废液中的重金属离子能被完全去除,EDTA和TOC的去除率分别达到了94.8%和86.6%。     

Incorporating sorption/desorption of organic pollutants into river water quality model

Preliminary research was conducted about how to incorporate sorption/desorption of organic pollutants with suspended solids and sediments into single-chemical and one-dimensional water quality model of Jinghang Canal.Sedimentation-resuspension coefficient k3 was deduced; characteristics of organic pollutants, concentrations and components of suspended solids/sediments and hydrological and hydraulic conditions were integrated into k3 and further into river water quality model; impact of sorption/desorption of organic pollutants with suspended solids and sediments on prediction function of the model was discussed. Results demonstrated that this impact is pronounced for organic pollutants with relatively large Koc and Kow, especially when they are also conservative and foc of riversuspended solids/sediments is high, and that incorporation of sorption/ desorption of organic pollutants into river water quality model can improve its prediction accuracy.     

两种改性剂对多氯联苯污染土壤协同热脱附影响研究

采用热脱附技术处理多氯联苯污染土壤已经成为了一种主要的场地修复方式。为提高热脱附效率,降低能耗,以典型电力电容器污染土壤为对象,采用2种改性剂(零价纳米铁和氢氧化钠)研究协同热脱附下多氯联苯的去除效率、分布特性及毒性当量。结果表明纳米铁和NaOH存在的条件下,有效提高了多氯联苯和毒性当量的去除效率,在较低温度下尤其显著,因此添加改性剂能够有效地促进热脱附过程。纳米铁的协同热脱附机理为显著强化了热脱附过程的传质传热,同时伴有一定的脱氯降解。NaOH的添加在较低温度下实现了较强的脱氯降解作用,加氢脱氯机理可用来解释协同热脱附过程中多氯联苯的脱氯反应过程。上述研究结果为多氯联苯污染土壤的场地修复提供理论基础。     

Effective removal of Cobalt(II) ions from aqueous solutions and nuclear industry wastewater using sulfhydryl and carboxyl functionalised magnetite nanocellulose composite: batch adsorption studies

A new adsorbent sulfhydryl and carboxyl functionalized magnetite nanocellulose composite [(MB-IA)-g-MNCC] was synthesized by graft co-polymerization of itaconic acid onto magnetite nanocellulose (MNCC) using EGDMA as cross linking agent and K₂S₂O₈ as free radical initiator. The adsorption occurs maximum in the pH 6.5. The best fitted kinetic model was found to be pseudo-second-order kinetics. Therefore the mechanism of Co(II) adsorption onto (MB-IA)-g-MNCC follows ion exchange followed by complexation. The Langmuir model was the best fitted isotherm model for the adsorption of Co(II) onto the (MB-IA)-g-MNCC. Simulated nuclear power plant coolant water samples were also treated with (MB-IA)-g-MNCC to demonstrate its efficiency for the removal of Co(II) from aqueous solutions in the presence of other metal ions. To recover the adsorbed Co(II) ions and also to regenerate the adsorbent to its original state 0.1?M HCl was used as suitable desorbing agent. Six cycles of adsorption-desorption experiments were conducted and was found that adsorption capacity of (MB-IA)-g-MNCC has been decreased from 97.5% in the first cycle to 84.7% in the sixth cycle. Recovery of Co(II) using 0.1?M HCl decreased from 93.2% in the first cycle to 79.3% in the sixth cycle.

Abbreviations: T: absolute temperature; q_e: amount adsorbed at equilibrium; q_t: amount adsorbed at time t; CELL: cellulose; Co: cobalt; C_e: concentration at equilibrium; C_HCl: concentration of HCl; C_NaOH: concentration of NaOH; C_A: concentrations of acid; C_B: concentrations of base; W_g: dry weight of composite; W_i: dry weight of MNCC; DS: energy dispersive spectra; EGDMA: ethylene glycol dimethacrylate; Ce: equilibrium concentration; K_L: equilibrium constant; F: Faradays constant; FTIR: Fourier transform infrared spectra; ΔG^o: free energy change; K_F: Freundlich adsorption capacity; 1/n: Freundlich constant; R: gas constant; D: grafting density; EC_o: initial concentration; IA: itaconic acid; IA-g-MNCC: itaconic acid-grafted-magnetite nanocellulose composite; b: Langmuir constant; MNCC: magnetite nanocellulose composite; Q⁰: Maximum adsorption capacity; (MB-IA)-g-MNCC: 2-mercaptobenzamide modified itaconic acid-grafted-magnetite nanocellulose composite; NC: nanocellulose; pH_pzc: Point of zero charge; K₂S₂O₈: potassium peroxy sulphate; k₁: pseudo-first-order rate constant; k₂: pseudo-second-order rate constant; SEM: scanning Electron Microscope; b_s: Sips adsorption capacity; Q_s: Sips maximum adsorption capacity; ΔH°: standard enthalpy change; ΔS°: standard entropy change; A: surface area; σ₀: surface charge density; 1/n_s: surface heterogeneity factor; VSM: vibrating sample magnetometer; V: volume of solution; W: weight of (MB-IA)-g-MNCC; M_composite: weight of the composite; XRD: X-ray diffraction     

热脱附-GC/MS法测定垃圾填埋场周围空气中氯代烃

采用热脱附-冷阱捕集-GC/MS法测定垃圾填埋场周围空气中24种氯代烃,通过试验优化并确定热脱附质谱的最佳处理条件。方法在5.00 mg/L～100 mg/L范围内线性良好,24种氯代烃的方法检出限为0.060μg/m~3～0.200μg/m~3,测定下限为0.240μg/m~3～0.800μg/m~3。空白加标回收率为91.8%～110%,6次测定结果的RSD均5%。实际样品测定结果为0.112 mg/m~3～0.412 mg/m~3,表明离垃圾填埋场最近的居民区环境中氯代烃为未检出或痕量分布,对生命体危害极低。     

聚丙烯酰胺对磷素在土壤中吸附-解析与迁移的影响

通过等温吸附-解析试验和土柱淋溶试验,研究了土壤(填土)经聚丙烯酰胺(PAM)处理后对磷素的吸附、解析规律以及磷素在土柱中迁移的影响.研究结果表明,和原土样相比,PAM减少了土壤在慢速吸附阶段对磷的吸附,不仅使土壤对磷的最大吸附量(Xm)降低,而且使被吸附磷的解析率升高;PAM与土壤复合后可以促进有效磷在土柱中向下迁移,增加淋溶液中磷的浓度.     

空气中联苯——联苯醚的气相色谱法测定

以国产硅胶担体为固体吸附剂,采集空气中联苯-联苯醚。经热解吸、制冷、闪蒸后,用气相色谱法测定。实验结果,在常温下,国产硅胶对联苯-联苯醚的吸附率达100％;解吸回收率为97.5％:变异系数<5％;方法的检测限为0.4μg。