PAFC对水体中持久性有机污染物PFOA的混凝效果

针对含全氟辛酸(PFOA)的工业废水及应对PFOA的污染突发事件,采用PAFC及其复配粘土矿物凹凸棒和沸石进行混凝实验,并对几个影响因素进行了考察。结果表明,在PAFC的最佳投加量10 mg/L时,PFOA和浊度的去除率分别达到70.25%和99.42%,PAFC混凝处理PFOA的效果优于PAC;pH值对PAFC去除PFOA有一定的影响,当pH大于6时有利于PFOA的去除;PFOA和浊度的去除率随原始浊度的增加而增加;活性炭、盐酸改性凹凸棒、盐酸改性沸石、CT-MAB改性的沸石复配PAFC均可提高PFOA的去除率;改性处理后的沸石应用于PFOA的处理中,有望降低处理成本。     

柠檬酸对褐土中DTPA提取态铜、镉含量及对紫花苜蓿吸收铜、镉的影响

为了阐述有机酸对土壤中重金属生物有效性的影响,通过盆栽实验,研究了Cu、Cd复合污染下柠檬酸对褐土中二乙基三胺五乙酸(DTPA)提取态铜和镉含量的影响,并探讨了柠檬酸对植物吸收铜、镉的影响。结果表明,土壤中DT-PA-Cu含量随柠檬酸添加量的增加而减小,添加高浓度铜(Cu 1 000)处理中,DTPA-Cu含量减小更明显。在添加低铜浓度(Cu600)处理下,柠檬酸添加量为2和12 mmol/kg时,土壤DTPA-Cu含量随土壤镉含量的增加而增加,而柠檬酸含量为5mmol/kg时,DTPA-Cu含量在低镉处理(Cd 1)时含量最低。紫花苜蓿中铜含量随柠檬酸添加量的增加明显降低。土壤中DTPA-Cd含量随柠檬酸添加量的增加而减小,且随铜添加量的增加而降低。紫花苜蓿中的镉含量随柠檬酸添加量的增加先增加后减小;在相同柠檬酸添加量处理时,紫花苜蓿中镉的含量随镉含量的增加而增加;在低镉处理下,铜的加入对较低柠檬酸浓度时紫花苜蓿镉含量影响不明显,但柠檬酸浓度为12 mmol/kg时,紫花苜蓿中镉含量随铜添加量的增加而明显增加。     

一种新型Fenton-流化床催化剂的制备及表征

非均相Fenton-流化床体系主要使用石英砂作为催化剂载体,该技术的实际应用由于催化剂活性寿命低、制备困难等原因而受到限制.提出了一种新型的Fenton-流化床催化剂——负载氧化铁陶粒.使用循环浸泡法制备的负载陶粒对苯甲酸模拟废水的处理效果良好.表征结果分析表明,载体表面铁含量大幅度上升,负载的氧化铁紧紧包裹在陶粒表面,且表面有大量缝隙,利于增加反应比表面积,而密度变化不大.该催化剂的催化活性重复性良好,重复使用4次后对苯甲酸模拟废水依然有较好的处理效果.使用该催化剂进行垃圾渗滤液的降解实验能在一定程度上减少亚铁的投加量,具有较好的实际应用前景.     

水环境中腐殖酸与镉离子结合作用的影响因素

通过测定不同化学条件下腐殖酸与镉离子作用后的游离态镉离子浓度及其结合率,研究各因素对腐殖酸与镉离子作用的影响。研究结果表明,pH值、离子强度、投加镉离子总浓度、腐殖酸浓度和反应温度均影响腐殖酸与镉离子的结合。pH值在4.5~6.5范围内,随pH值升高,腐殖酸与Cd²⁺的结合率增大,游离态Cd²⁺浓度减少。溶液的离子强度增大对结合反应有抑制作用。投加Cd²⁺总浓度的增大会导致结合态Cd²⁺浓度和游离态Cd²⁺浓度逐渐增加,而其结合率逐渐减小。腐殖酸浓度逐渐增大,使Cd²⁺和腐殖酸的结合率逐渐增大。在20℃~50℃范围内时,随反应温度升高,游离态Cd²⁺浓度逐渐减小,其结合率逐渐增加。     

几种印染助剂对壳聚糖稳定纳米铁去除酸性品红的影响

以氯化铁为铁源,硼氢化钠为还原剂,壳聚糖为稳定剂,采用液相还原法制备壳聚糖稳定纳米铁（CS-nZⅥ）;研究了印染废水中常见助剂NaNO₃、Na₂SO₄、NaH₂PO₄、K₂Cr₂O₇、EDTA二钠盐存在下,超声波辅助CS-nZⅥ对酸性品红（AF）降解的影响。结果表明,反应15 min,0.01 g CS-nZⅥ对25 mL、100 mg/L AF的去除率高达99.9%;各种助剂的存在使得纳米铁表面不同程度失活,阻碍反应的进行,使得AF的去除率下降。NaNO₃、K₂Cr₂O₇、EDTA二钠盐与纳米铁发生反应,与AF存在明显的竞争作用。重复利用实验表明,CS-nZⅥ重复利用7次仍具有一定的反应活性。此外,CS-nZⅥ对加标（50 mg/L）实际废水中AF的去除率达到99%以上,表明CS-nZⅥ是一种潜在的环境修复材料。     

交联壳聚糖/沸石复合吸附剂的制备及性能

用沸石负载由缩水甘油基三乙基氯化铵交联的壳聚糖,制得了性能良好的交联壳聚糖/沸石复合吸附剂。研究了该吸附剂应用性能的影响因素,探讨了该吸附剂的吸附性、沉降性和重复使用性,利用FTIR仪和高倍透射电子显微镜对该吸附剂的结构进行了表征。实验结果表明:壳聚糖的交联度为0.93、交联壳聚糖与沸石的质量比为0.045时,制得的交联壳聚糖/沸石复合吸附剂对腐殖酸的去除率可达81.4%,吸附量为4.07mg/g;交联壳聚糖/沸石复合吸附剂对腐殖酸的吸附性能较沸石有显著提高,沉降时间较交联壳聚糖明显缩短;经二次洗脱后腐殖酸去除率仍可达80.2%,腐殖酸吸附量为4.01mg/g。     

改性蚁酸木质素的制备与应用

采用加拿大一枝黄花茎杆为原料提取蚁酸木质素,通过氧化或接枝复合的方法对蚁酸木质素进行改性,对改性产物进行了FTIR和SEM表征。实验结果表明：接枝复合改性产物中存在-CONH的接枝复合链,氧化改性产物基本保持了蚁酸木质素原来的吸收峰;采用接枝复合改性产物处理初始质量浓度为50 mg/L的亚甲基蓝废水,在废水pH 7、吸附时间4 h、改性产物加入量22 mg/mL的条件下,亚甲基蓝去除率为90.94%;采用氧化改性产物处理相同亚甲基蓝废水,在废水pH 10、吸附时间12 h、改性产物加入量22 mg/mL的条件下,亚甲基蓝去除率为81.93%。     

紫外辐照-催化湿式过氧化氢氧化技术处理酸性大红GR染料废水

采用自制的负载型CuO-ZnO-CeO2/γ-Al2O3催化剂,常温常压下通过紫外辐照-催化湿式氧化技术处理酸性大红GR模拟染料废水。考察了催化剂加入量、H2O2加入量、废水pH、反应时间、初始酸性大红GR质量浓度等对废水脱色率的影响。实验得到最佳工艺条件为初始酸性大红GR质量浓度200mg/L,催化剂加入量10.0g/L,H2O2加入量2.0mL/L,废水pH4,反应时间2h。最佳工艺条件下废水脱色率达99.33%。     

Salicylic acid involved in the regulation of nutrient elements uptake and oxidative stress in Vallisneria natans (Lour.) Hara under Pb stress

In this study, the alterations in nutrient elements content, reactive oxygen species level and antioxidant response were studied in leaves of Vallisneria natans (Lour.) Hara exposed to salicylic acid (SA, 10 or 100 μM), or Pb (50 μM) or their combinations for 4 d. No significant alterations in Mn and Ca content were observed but content of Cu, Zn, Fe and P decreased in plants exposed to SA alone. SA application inhibited the uptake of Pb and partially reversed Pb-induced the alterations in Mn, Ca and Fe content in leaves of V. natans exposed to 50 μM Pb. The decreased chlorophyll (a + b) and increased malondialdehyde and O²⁻ and H₂O₂ content were detected in plants exposed to 100 μM SA, 50 μM Pb, 10 μM SA + 50 μM Pb or 100 μM SA + 50 μM Pb. Application SA partially inhibited Pb-induced the increase of malondialdehyde, O²⁻ and H₂O₂ content. 100 μM SA decreased the activity of NADH oxidase and the content of non-protein thiols, carotenoids and ascorbic acid and increased the content of dehydroascorbate in plants treated with or without Pb. SA alone decreased the ascorbate peroxidase activity and increased the catalase and peroxidase activity, while SA application increased catalase activity but had no significant effect on ascorbate peroxidase and peroxidase activity in V. natans exposed to Pb. The results indicate that SA involves in the regulation of Pb uptake, nutrient balance and oxidative stress.     

Determination of o-phthalic acid in snow and its photochemical degradation by capillary gas chromatography coupled with flame ionization and mass spectrometric detection

Phthalic acid and its photochemical degradation has been determined in snow and rainwater samples collected during winters (2003-2010) in the Southeast of Massachusetts using capillary gas chromatography (GC) with flame ionization and mass spectrometric detection. Water samples were dried using a rotary evaporator and derivatized with a 14% BF₃/methanol reagent before GC analysis. The developed method proved simple and accurate. Phthalic acid was found in snow samples collected in a concentration range of 7.22-76.5 nM. The photodegradation of phthalate was carried out under 300 nm UV light. The direct photodecomposition of the acid is slow (5% h⁻¹). However, the addition of dissolved Fe(III) species at 2.0 μM accelerated the light-induced degradation of phthalic acid by 3.5 times in the atmospheric water samples. Photodegradation rates of phthalic acid increases with decreasing pH value of water samples in the range of pH 2.8-4.5.