单宁基酚胺型螯合树脂的制备及对Cr(Ⅵ)的吸附

杨梅单宁先与氯化亚砜反应制得氯代单宁,再与聚乙烯亚胺交联合成单宁基酚胺型螯合树脂.通过FTIR、SEM、EDS和XPS对单宁基酚胺型螯合树脂的结构进行表征,并考察了螯合树脂对Cr(Ⅵ)的吸附性能.在单宁的分子结构侧链引入氨基,能有效改善单宁基螯合树脂对Cr(Ⅵ)的吸附性能,螯合树脂对Cr(Ⅵ)的吸附主要为还原吸附,铬主要以Cr(Ⅲ)的形式吸附到树脂上;在温度为318 K、pH为2.0、Cr(Ⅵ)初始质量浓度为500 mg/L,吸附时间420 min时,单宁基酚胺型螯合树脂对Cr(Ⅵ)的最大吸附量达到364.46 mg/g;当Cr(Ⅵ)初始质量浓度低于20 mg/L时,单宁基酚胺型树脂对铬的吸附率达到95％以上;单宁基酚胺型螯合树脂对Cr(Ⅵ)的吸附过程符合Langmuir等温吸附模型和准二级吸附动力学方程.该树脂在含铬废水处理方面具有潜在的应用前景.     

单宁基阳离子型吸附树脂的制备及吸附性能研究

以3-氯-2-羟丙基三甲基氯化铵为改性剂对单宁基酚醛树脂进行表面改性制备单宁基阳离子型吸附树脂,利用红外分析和元素分析对单宁基阳离子型吸附树脂的结构进行了表征,并探讨了该树脂对直接染料吸附性能。结果表明,单宁基酚醛树脂表面引入了季铵基团;单宁基酚醛树脂经季铵化改性后对直接染料具有较好的吸附效果,最大吸附量达到531.1 mg/g;在直接染料质量浓度低于0.2 g/L时,单宁基阳离子型吸附树脂对直接染料的吸附率高达96%以上;单宁基阳离子型吸附树脂对直接染料的吸附符合Langmuir等温吸附模型。该树脂在阴离子染料废水处理方面具有潜在的应用前景。     

羧甲基纤维素-单宁基吸附树脂的制备及性能研究

制备了羧甲基纤维素-单宁基吸附树脂,并研究了吸附树脂对亚甲基蓝的吸附性能。羧甲基纤维素与单宁结合,通过羧甲基纤维素羧基与单宁酚羟基的协同作用,能有效提高吸附树脂对亚甲基蓝的吸附性能,最大吸附容量可达1 300 mg/g。在亚甲基蓝溶液初始质量浓度为1 000 mg/L,吸附剂投加质量浓度为1.5 g/L时,吸附树脂对亚甲基蓝的吸附率可达98%以上,且羧甲基纤维素-单宁基吸附树脂具有较好的重复使用性能。     

氨基硫脲-戊二醛螯合树脂的合成及对Cr(Ⅵ)的吸附性能

以氨基硫脲和戊二醛为原料,用一步法合成了一种新型的含硫和氮原子的螯合吸附树脂。对该树脂进行扫描电子显微镜、红外光谱、元素分析表征,并测定了螯合树脂对Cr(VI)离子的吸附性能以及研究了树脂对Cr(VI)离子吸附的原理。结果表明,树脂对Cr(VI)离子吸附最佳p H为2,最大的吸附量达到345 mg·g-1,该吸附剂能再生,可应用于含Cr(Ⅵ)废水的分离或富集。     

用732强酸性阳离子交换树脂去除铬酸盐钝化液中的锌离子

对732强酸性阳离子交换树脂再生铬酸盐钝化液进行了探索。研究了交换处理时间、溶液初始pH、Zn(II)初始浓度及树脂用量对树脂吸附的影响,并考察了树脂的脱附和再生性能。结果表明,该树脂对Zn(II)的吸附速率快,30 min达到吸附平衡,最佳吸附pH为3~6。用树脂再生钝化液不会对Cr(VI)浓度产生影响,能达到"去锌保铬"的目的。该树脂对Zn(II)的吸附符合Langmuir吸附等温模型,为单分子层吸附,具有吸附饱和性,饱和吸附量约为85.6 mg/g。     

啤酒酵母吸附Cr（VI）的动力学及热力学研究

研究啤酒酵母对溶液中铬(VI)的吸附效果和机理,通过红外对吸附前后菌体表面特征分析,表明Cr (VI)与菌体表面基团发生配位络合反应.结果表明,在温度为35 ℃,pH=2,Cr(VI)初始浓度为20 mg/L时达到最大吸附量,最大吸附量为4.19 mg/g.酵母菌对Cr(VI)的吸附行为基本符合Langmuir方程,并且在 25,30和35 ℃条件下的理论最大吸附量qmax分别为4.472,4.533,4.702 mg/g.动力学研究表明,反应在240 min吸附基本达到平衡状态,准二级动力学模型能够更好的描述吸附过程.不同温度下的吸附热力学显示,该吸附过程为自发的吸热反应.     

新型纤维素螯合吸附剂对Cr(Ⅵ)的吸附研究

研究了半皂化偕胺肟基纤维素吸附剂AOSC对Cr(Ⅵ)的吸附,探讨了各种因素对吸附效果的影响。结果表明,当Cr(Ⅵ)的初始质量浓度为100mg/L时,最佳的吸附条件为:吸附液pH值为2,吸附时间2h,吸附温度35℃。在此条件下AOSC的吸附容量和Cr(Ⅵ)去除率分别达到49.8mg/g和99.5%。吸附性能对比实验表明,AOSC对Cr(Ⅵ)的吸附效果优于纤维素基离子交换剂和偕胺肟基螯合吸附剂。     

铝镁铁三元类水滑石对Cr(VI)的吸附性能研究

采用共沉淀法合成了铝镁铁三元类水滑石,考察了该类水滑石对水溶液中Cr(VI)的吸附性能。结果表明:在温度为20℃,初始pH值为7的条件下,吸附剂对Cr(VI)的吸附平衡时间约为15min,平衡时吸附量为8.37mg/g;吸附量随初始pH值的降低而增大,当初始pH值为2.8时吸附量达到9.55mg/g;吸附量还随着初始质量浓度的增加而增大,但当初始质量浓度超过20mg/L后吸附量反而下降。     

铅锌尾矿对Cr(Ⅵ)吸附性能的研究

用铅锌尾矿作为吸附剂,研究了铅锌尾矿对Cr(VI)的吸附性能。考察了铅锌尾矿的目数和用量、吸附时间对吸附性能的影响。探索了铅锌尾矿吸附Cr(VI)的热力学和动力学特性。实验结果表明,吸附的最佳条件是:Cr(VI)初始浓度为20 mg/L时,铅锌尾矿目数为80、尾矿的量为8 g以及吸附时间48 h的条件下,铅锌尾矿对Cr(VI)吸附性能较高;铅锌尾矿对Cr(VI)的吸附符合Langmuir等温线和准二级动力学方程。     

花生油饼对Cr(Ⅵ)的吸附研究

以花生油饼作为吸附剂,对Cr(VI)进行吸附处理。通过单因素实验,探究了溶液初始质量浓度、吸附剂投加量、吸附时间、搅拌速率及溶液p H等因素对吸附性能的影响。在此基础上进行了正交试验,其结果表明花生油饼吸附Cr(VI)的最佳吸附条件为:100 m L初始质量浓度为15 mg/L的模拟含铬废水,吸附剂用量为1.0g,p H为2.0,搅拌速率为240 r/min,吸附时间为120 min。其中p H和吸附时间是影响去除率的两个重要因素,在该吸附条件下,花生油饼对Cr(VI)的去除率为97%,Cr(VI)的剩余质量浓度为0.45 mg/L,小于《污水综合排放标准》(GB8978—1996)中第一类污染物的排放限定值。等温吸附实验表明,花生油饼对Cr(VI)的吸附用弗罗因德利希吸附等温方程拟合更好。     

聚丙烯酸复合铝改性膨润土制备及其对Cr(VI)的吸附

为改善膨润土对Cr(VI)的吸附性能,用铝、丙烯酸聚合及十六烷基三甲基溴化铵改性合成聚丙烯酸复合铝改性膨润土。采用X射线衍射、红外光谱和扫描电子显微镜对天然膨润土和改性膨润土进行表征。结果表明,在25℃、溶液pH=5~6时,0.5 g吸附剂对200 mL浓度为20 mg/L Cr(VI)的平衡吸附量为1.996 mg/g,平衡吸附时间为130 min,且固液分离容易。吸附过程较好地符合Lagergren二级吸附动力学方程和Freundlich等温吸附方程,颗粒状吸附剂对Cr(VI)的吸附以络合吸附为主。     

离子交换法处理含Cr(Ⅵ)废水的研究

采用201×7强碱性阴离子交换树脂处理模拟含Cr(Ⅵ)废水,探讨了废水酸度、交换时间、浓度对Cr(Ⅵ)去除率的影响以及树脂再生所需的合适温度和再生剂浓度。结果表明,201×7强碱性阴离子交换树脂处理模拟含Cr(Ⅵ)废水,具有交换容量大、交换效果好、树脂再生条件较简单等优点。并对实际含铬废水进行了处理,废水中Cr(Ⅵ)的初始浓度为1 540 mg/L,处理量达52 BV(床体积)时,出水中Cr(Ⅵ)的浓度仍小于0.5 mg/L,达到国家排放标准。树脂交换容量约80 mg/g。用8%NaOH溶液,在50℃条件下进行再生效果较好,再生率大于95%,可实现树脂的重复使用。     

Removal of Hexavalent Chromium by Different Modified Spruce Bark Adsorbents

In this work, spruce bark was used as a raw material to remove Cr(VI) ions from aqueous solutions. Three kinds of chemically modified bark adsorbents were prepared by treatment with formaldehyde (FB), dilute sulfuric acid (AB), and concentrated sulfuric acid (CB), respectively. The chemical modifications mainly changed the relative lignin content in the bark. Lower pH facilitated the adsorption of Cr(VI) ions because reduction of Cr(VI) ions to Cr(III) ions occurred during the adsorption process which consumed a large amount of H⁺ ions. Higher temperature accelerated the adsorption process, owing to the endothermic nature of the redox reaction. At initial solution pH around 1, the adsorption capacities of Cr(VI) ions on FB, AB, and CB were as high as 423, 503, and 759 mg/g, respectively, which were much higher than the reported adsorption capacities by other agricultural and forest biosorbents in the literatures. XPS analysis revealed the adsorption mechanism was adsorption-coupled reduction involving the electron-donor groups of lignin moieties.     

球形聚合单宁-纤维素树脂的制备及吸附性能

单宁与多聚甲醛交联合成单宁酚醛聚合物,再以环氧氯丙烷为交联剂,将单宁酚醛聚合物与纤维素通过反相悬浮交联制备球形聚合单宁-纤维素树脂。通过傅里叶变换红外光谱（FTIR）、扫描电子显微镜（SEM）对球形聚合单宁-纤维素树脂的结构进行了表征,并考察了球形聚合单宁-纤维素树脂对盐酸小檗碱的吸附性能。结果表明,球形聚合单宁-纤维素树脂具有多孔的结构,树脂网络中含有大量的酚羟基;球形聚合单宁-纤维素树脂对盐酸小檗碱具有较好的吸附性能,当盐酸小檗碱浓度为600 mg·L^-1、吸附温度为298 K时,最大饱和吸附量可达245.92mg·g^-1;球形聚合单宁-纤维素树脂对盐酸小檗碱的吸附过程符合Langmuir吸附等温模型和准二级吸附动力学方程,热力学研究数据表明球形单宁-纤维素树脂对盐酸小檗碱的吸附是一个自发放热的物理吸附过程。该树脂在分离提纯生物碱方面具有潜在的应用前景。     

颗粒活性炭载纳米零价铁去除水中的Cr(Ⅵ)

以Fe2+溶液为原料、NaBH4为还原剂,采用传统液相还原技术合成了颗粒活性炭(GAC)载纳米零价铁(nZVI)复合材料GAC-nZVI,用扫描电镜对GAC-nZVI进行表征,通过间歇实验考察了其对去除Cr(VI)的影响。结果表明,GAC能阻止nZVI颗粒聚集,合成的GAC-nZVI能有效去除水中的Cr(VI)。在Cr(VI)初始浓度50 mg/L、温度40℃和pH=2.0、投加GAC-nZVI 3.0 g/L的条件下反应5 min,Cr(VI)去除率为99.4%。pH=2.0?4.0时,处理后水中总铬浓度均低于1 mg/L,表明残留少量Cr(III)。随pH值和Cr(VI)浓度增加,Cr(VI)去除率降低;随反应温度和GAC-nZVI投加量增加,Cr(VI)去除率增加。准一级动力学模型可用于描述Cr(VI)的去除过程。相同条件下,GAC-nZVI去除Cr(VI)的反应速率常数达0.19797 min?1,为原颗粒活性炭反应速率常数0.0023 min?1的86倍。随pH值降低或反应温度和GAC-nZVI投加量增加,反应速率常数增加。     

交联薯渣黄原酸酯对废水中Cr(Ⅵ)的吸附研究

交联薯渣黄原酸酯(CCX)废水中Cr(Ⅵ)离子的吸附,探讨了pH值、温度、吸附时间、CCX含硫量、Cr(Ⅵ)初始浓度等因素对其吸附效果的影响。结果表明,当CCX加入量为理论加入量的3.0倍时,pH为2.5,在45℃下搅拌反应50 min,对Cr(Ⅵ)的吸附容量为37.76 mg/g,去除率达到99.69%,处理后的废水中Cr(Ⅵ)浓度为0.15 mg/L,低于国标排放标准(0.5 mg/L)。并通过红外光谱和热重分析,对CCX吸附Cr(Ⅵ)的机理进行了探讨。     

Study on adsorption of Cu(II)–Cr(VI) binary system by carbonized Eupatorium adenophorum

We first report a mechanism study on the adsorption of Cu(II)-Cr(VI) binary mixture by a novel low-cost adsorbent, carbonized Eupatorium adenophorum. The influences by pH value, dosage, initial concentration, temperature, and adsorption time on its performance to absorb copper and chromium were investigated. The experimental data were fitted according to the Langmuir and Freundlich adsorption isotherm models, the pseudo-first-order kinetics, the pseudo-second-order kinetics, and the intra-particle diffusion model. The results indicated that when the reaction system was with its pH = 5, the dosage of carbonized Eupatorium adenophorum was 0.1 g, the adsorption time was 30 min, and the temperature was 25°C; the adsorption capacities for Cu(II) and Cr(VI) reached 27.62 mg/g and 9.68 mg/g, respectively. The process of carbonized Eupatorium adenophorum to absorb Cr(VI) is also accompanied by redox reactions. The Langmuir model and the pseudo-second-order model can better ?t the experimental data. Observation by fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) found no significant change of functional groups before and after the adsorption by carbonized Eupatorium adenophorum, and this adsorption process is mainly a physical adsorption.     

Red mud (aluminum industrial waste): An eco-friendly treatment of electroplating effluent

In this work, aluminum industrial waste, red mud (RM), was activated to verify its potential in the management of electroplating wastewater containing hexavalent chromium (Cr(VI)). A comparison between the adsorption capabilities of RM and activated red mud (ARM) towards Cr(VI) from aqueous solutions was made. The effects of several parameters were evaluated. The adsorbents were characterized by field emission scanning electron microscopy (FESEM), Fourier transmission infrared spectroscopy (FTIR), x-ray diffraction (XRD), zeta potential, and thermogravimetric analysis (TGA). The particle size was observed as 23.59 nm. The ARM demonstrated an acceptable adsorption capacity of 25.641 mg/g at a pH of 2, adsorbent dosage of 2 g/L, initial Cr(VI) concentration of 100 mg/L, at 25°C. The experimental data is in good agreement with Langmuir adsorption isotherm. The kinetic study was performed to verify that the adsorption follows pseudo-second-order kinetics. In addition, the ARM showed decent recyclability for adsorbing Cr(VI) as even after three adsorption cycles, and the adsorption capacity was reduced by ~30%. The results recommend ARM to be an efficient and cost-effective adsorbent for Cr(VI) removal from industrial wastewater.     

氧化改性橡椀单宁对铜离子溶液的吸附性

以橡椀栲胶为原料,通过双氧水氧化降解改性,研究水解类橡椀单宁改性后对铜离子溶液的吸附沉淀以及pH值、金属溶液初始浓度对铜离子吸附沉淀容量的影响和规律。结果表明,氧化橡椀单宁对Cu2+的吸附平衡符合Freundlich方程。改性后吸附沉淀容量受初始浓度影响较大,初始浓度为20 mg/L时基本不发生吸附沉淀,试验最大初始浓度100 mg/L时吸附量达到39.300 mg/g。