Material conversion from paper sludge ash in NaOH solution to synthesize adsorbent for removal of Pb^2＋, NH^4＋ and PO4^3- from aqueous solution

Material conversion from paper sludge ash (PSA) in NaOH solution was attempted to synthesize the adsorbent for removal of inorganic pollutants, such as Pb2+, NH4 + and PO4 3?? from aqueous solution. PSA of 0.5 g was added into 10 mL of 3 mol/L NaOH solution, and then heated at 80, 120, and 160°C for 6–48 hr to obtain the product. PSA mainly composed of two crystalline phases, gehlenite (Ca2Al2SiO7) and anorthite (CaAl2Si2O8), and amorphous phase. Hydroxysodalite (Na6Al6Si6O24 8H2O) was formed at 80°C, and anorthite dissolved, whereas gehlenite remained una ected. Katoite (Ca3Al2SiO4(OH)8) was formed over 120°C, and hydroxycancrinite (Na8(OH)2Al6Si6O24 2H2O) was formed at 160°C, due to the dissolution of both gehlenite and anorthite. Specific surface areas of the products were almost same and were higher than that of raw ash. Cation exchange capacities (CECs) of the products were also higher than that of raw ash, and CEC obtained at lower temperature was higher. Removal abilities of products for Pb2+, NH4 +, and PO4 3?? were higher than that of raw ash.With increasing reaction temperature, the removal e ciencies of Pb2+ and NH4 + decreased due to the decrease of CEC of the product, while removal e ciency for PO4 3?? was almost same. The concentrations of Si and Al in the solution and the crystalline phases in the solid during the reaction explain the formation of the product phases at each temperature.     

白腐真菌处理阳离子红GTL废水的实验研究

采用白腐真菌去除阳离子红GTL,考察了温度、投菌量、阳离子红GTL浓度、pH、葡萄糖投加量等因素对阳离子红GTL去除效果的影响。结果表明,白腐真菌对阳离子红GTL的最佳降解条件为温度30℃,阳离子红GTL初始浓度200 mg/L,投菌量10 g/L。在此条件下,阳离子红GTL模拟废水经白腐真菌降解45 h处理后,脱色率达98.9%,COD值下降了75%。该菌降解阳离子红GTL符合一级反应动力学。     

改性膨润土应急截留液态有机物的性能及机制

用长碳链季铵盐阳离子表面活性剂改性膨润土,研究其对典型液态有机物(苯、氯苯、硝基苯、柴油)的截留性能及作用机制,并进行了中试规模的模拟应急处置试验.改性膨润土对液态有机物的单位截留量(2.83～9.01 g.g-1)明显高于常规截留剂(0.28～1.17 g.g-1).表面活性剂的性质、添加量及有机物本身的黏度是影响改性膨润土对液态有机物截留性能的重要因素,其中以溴化十六烷基三甲基铵(CTMAB)为改性剂且其添加量为100%CEC的改性膨润土的截留性能最佳.在液态有机物泄漏模拟处置中,改性膨润土应急截留装置可在短时间内(30 min)完成对液态有机物90%以上的就地截留.研究表明改性膨润土截留液态有机物的主要作用机制是表面活性剂的改性处理增强了改性膨润土的疏水性,并增大了其层间距,从而提高了其对液态有机物的截留性能.     

应用多思单元的离子色谱法测定降水中六种阳离子

笔者通过研究建立了应用单标多点校正和英蓝超滤单元的非抑制电导离子色谱法测定降水中Li+、Na+、NH4+-N、K+、Ca2+、Mg2+6种阳离子的方法。该方法操作简单,样品无需过滤即可上机分析测定;检出限低,范围在0.005～0.04 mg/L;重复测定相对标准偏差小于5%,加标回收率稳定在96.7%～104.6%;线性范围广,待测离子之间无明显干扰,可同时快速测定降水中不同浓度的阳离子。同时该方法降低了标准品配制和样品前处理的复杂性。     

水中污染物对阳离子交换膜分离去除Cu2+的影响

基于Donnan dialysis原理,在无外加电压作用下采用阳离子交换膜分离去除原水中的Cu2+,研究原水中可能出现的无机颗粒物,有机物质,EDTA酸、氨水、Fe3+、表面活性剂等对阳离子交换膜分离去除Cu2+效果的影响.研究表明:原水中添加二氧化硅、腐殖酸、EDTA酸、氨水、Fe3+、表面活性剂等物质,在长时间运行后均会对离子交换膜去除Cu2+有不同程度的影响;二氧化硅和非离子表面活性剂等污染物不会和膜及Cu2+发生物理化学反应,对膜去除Cu2+效果影响较小,相比空白样,Cu2+去除率下降约4%;氨水、阴离子表面活性剂等会导致Cu2+发生沉淀反应,腐殖酸会吸附Cu2+,使原水中游离态Cu2+浓度显著降低约50%;EDTA酸、氨水、阴离子表面活性剂等会与Cu2+形成络合物,对去除Cu2+有严重影响,相比空白样, Cu2+去除率分别下降约100%(EDTA酸)、78%(氨水)、56%(阴离子表面活性剂);阳离子表面活性剂存在时,其会大量占据膜内空间,Cu2+基本无去除;Fe3+在弱酸性或中性水中会水解生成氢氧化铁胶体,对去除Cu2+有一定影响,相比空白样, Cu2+去除率下降约12%.     

Enhanced adsorption of phosphate by loading nanosized ferric oxyhydroxide on anion resin

Ferric oxyhydroxide loaded anion exchanger （FOAE） hybrid adsorbent was prepared by loading nanosized ferric oxyhydroxide （FO） on anion exchanger resin for the removal of phosphate from wastewater. TEM and XRD analysis confirmed the existence of FO on FOAE. After FO loading, the adsorption capacity of the hybrid adsorbent increased from 38.70 to 51.52mg.g-1. Adsorption processes for both FOAE and anion resin were better fit to the pseudo first order model. Batch adsorption experiments revealed that higher temperature （313K）, higher initial phosphate concentration （50 mg.L-1） and lower solution pH （pH value of 2） would be more propitious to phosphate adsorption. Competition effect of coexisting anions on phosphate removal can be concluded as sulfate 〉 nitrate 〉 chloride. Freundlich isotherm model can describe the adsorption of phosphate on FOAE more accurately, which indicated the heterogeneous adsorption occurred on the inner-surface of FOAE.     

Cation exchange resin supported nanoscale zero-valent iron for removal of phosphorus in rainwater runoff

Self-made cation exchange resin supported nanoscale zero-valent iron （R-nZVI） was used to remove phosphorus in rainwater runoff. 80% of phosphorus in rainwater runoff from grassland was removed with an initial concentration of 0.72 mg. L-1 phosphorus when the dosage of R-nZVl is 8 g per liter rainwater, while only 26% of phosphorus was removed when using cation exchange resin without supported nanoscale zero-valent iron under the same condition. The adsorption capacity of R-nZVI increased up to 185 times of that of the cation exchange resin at a saturated equilibrium phosphorous concentration of 0.42 mg. L-1. Various techniques were implemented to characterize the R-nZVI and explore the mechanism of its removal of phosphate. Scanning electron microscopy （SEM） indicated that new crystal had been formed on the surface of R-nZVI. The result from inductive coupled plasma （ICP） indicated that 2.1% of nZVI was loaded on the support material. The specific surface area was increased after the load of nanoscale zero-valent iron （nZVI）, according to the measurement of BET-N2 method. The result of specific surface area analysis also proved that phosphorus was removed mainly through chemical adsorption process. X-ray photoelectron spectroscopy （XPS） analysis showed that the new product obtained from chemical reaction between phosphate and iron was ferrous phosphate.     

阳离子聚丙烯酰胺改性膨润土对靛蓝的吸附性能

采用CPAM(阳离子聚丙烯酰胺)改性膨润土作为吸附材料,对靛蓝进行吸附研究,考察膨润土投加量、溶液的pH、反应温度、吸附时间及溶液初始ρ(靛蓝)对吸附效果的影响,并对膨润土的性能进行了表征. 结果表明,CPAM改性膨润土对靛蓝的去除率随着投加量的增加迅速增加,最佳投加量为3g/L,达到吸附平衡所需时间为40min. 当溶液pH为4.0~10.0时,CPAM改性膨润土均能保持较大吸附量,并且pH的变化对吸附量影响较小;当溶液pH大于10.0时,吸附量明显降低. CPAM改性膨润土对靛蓝的吸附动力学符合拟一级动力学方程,热力学符合Langmuir和Freundlich方程,回归系数均达0.99以上;pH为6.0时,最大吸附量为5287.0mg/g,是未改性膨润土吸附量的21.4倍,吸附性能比未改性膨润土有显著提高. 通过比表面积的测定及红外光谱和透射电子显微镜分析发现,CPAM与钠基膨润土土层中的阳离子发生离子交换反应,CPAM改性膨润土疏水性增强,层间结构发生变化,同时外比表面积增大,对有机染料的吸附作用增加,说明改性后的膨润土在结构和性能上明显优于未改性膨润土.      

强力霉素在凹凸棒土上的吸附行为

通过等温吸附平衡法研究了强力霉素在凹凸棒土上的吸附行为,考察了pH、反应时间、离子强度和离子类型等因素对吸附的影响,探讨了吸附机理.结果表明,pH=8.5时,饱和吸附容量最大,为293.35μmol.g-1;强力霉素在凹凸棒土上的吸附可用Langmuir型等温方程和准二级动力学方程很好地拟合;离子强度对强力霉素的吸附影响不是很明显;0.05 mol.L-1NaOH能显著地将强力霉素从凹凸棒土上解吸下来.红外表征结果说明凹凸棒土对强力霉素的吸附可能是化学吸附,酸性条件下,强力霉素主要通过阳离子交换、静电作用、氢键作用等吸附在凹凸棒土上,部分H+可能通过强力霉素质子化吸附到凹凸棒土上.弱碱性条件下主要通过水桥接,与凹凸棒土层间阳离子配位以及结合于凹凸棒土边缘吸附位点达到吸附.     

土壤盐化过程中阳离子对镉的形态分布影响

以硝酸盐为例,实验分析了无机盐阳离子对碱性盐化土壤中镉形态分布的影响。结果表明,随着Na＋、K＋、Ca2＋、Mg2＋等阳离子进入土壤,土壤中镉的有效态含量增加,对镉有明显的活化作用;随着Na＋、K＋、Ca2＋、Mg2＋浓度的增加,有效态镉的含量进一步增加,镉有效态的增加幅度可达到55.46%～68.39%;土壤镉的其它各形态含量都随着Na＋、K＋、Ca2＋、Mg2＋等的加入而减少,其中碳酸盐态的减少量为23.61%～63.14%,铁锰氧化态的减少量为10.77%～25.66%,有机态的减少量为18.11%～54.68%,残渣态的减少量为2.14%～12.78%。不同种类阳离子对土壤中镉形态变化的影响程度有差异,钙离子对土壤中镉的吸附竞争能力最强,镁离子次之,而钠离子和钾离子对镉的吸附竞争能力相似。