用于降氟的亚粘土改性方法与吸附作用机理研究

研究了改性方法和改性条件对用于降氟的亚粘土除氟性能的影响,得出了每一种改性方法的最佳改性条件,探讨了改性亚粘土的吸附机理.研究表明,改性亚粘土除氟率高、工作交换容量大,除氟率最高达100%.最大工作交换容量达243.30mg·kg-1.改性亚粘土降氟功能归因于所含针铁矿和伊利石对于F-的专性吸附.     

椰壳生物炭对多种重金属在广东水稻土中的吸附解吸特性影响

土壤中有毒有害重金属会造成环境污染并危害人体健康。本文基于OECD 106实验准则,采用批量平衡实验方法,研究了多种有效态重金属镉（Cd²⁺）、钴（Co²⁺）和铜（Cu²⁺）在广东省水稻土中的吸附解吸行为特征以及添加椰壳生物炭对吸附解吸行为的影响,并探讨了pH值、温度和添加炭含量对吸附率的影响。结果表明,3种重金属在土壤中的吸附平衡时间为25 h,解吸平衡时间为30 h,添加质量浓度5%椰壳生物炭可使土壤对3种重金属的吸附率提高11.6%~20.0%,重金属离子在土壤中的吸附为不可逆吸附,具有明显滞后效应,Cd²⁺、Co²⁺和Cu²⁺的解吸滞后系数分别为33.838、1.347和0.972。在本试验条件下,土壤溶液的pH值随椰壳生物炭含量的增加而增大,温度和含炭量对吸附率的影响呈良好的线性关系（r²>0.951）。这表明,在土壤中施用椰壳生物炭能有效缓解土壤中的重金属污染。     

Heavy metals uptake from aqueous solutions using marine algae (Colpomenia sinuosa): kinetics and isotherms

The adsorption of copper, zinc, cobalt, lead and cadmium ions onto Colpomenia sinuosa was studied as a function of contact time, initial metal ion concentration and initial pH. In addition, desorption studies were performed. Characterisation of this adsorbent was also confirmed by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) analysis. Batch adsorption experimental data were analysed using Langmuir, Freundlich and Dubinin–Raduschkevich (D–R) adsorption isotherms. The results indicated that the biosorption equilibrium was well described by both the Freudlich and D–R isotherms. Moreover, sorption kinetics was performed and it was observed that equilibrium was reached in<60 min, which could be described by the pseudo-second-order kinetic model for all heavy metals. The sorption of heavy metals onto the biomass was largely dependent on the initial solution pH. The elution efficiency for heavy metal ions desorption from C. sinuosa was determined for 0.1 M HCl, 1.0 M HCl and 1.0 M HNO₃. Desorption efficiency and also adsorption capacity were highest for Pb(II). The results indicate that C. sinuosa has great potential for the removal of heavy metals in an ecofriendly process.     

1,3,5-triazine-triethylenetetramine polymer: an efficient adsorbent for removal of Cr(VI) ions from aqueous solution

The synthesis of 1,3,5-triazine-triethylenetetramine (TATETA), its characterization by infrared spectroscopy and elemental analysis, and its application for removal of Cr(VI) ions from aqueous solution is reported. The effects of pH, contact time, initial concentration of Cr(VI), sorbent dose, and temperature on adsorption were investigated and optimized by batch adsorption experiments. Adsorption was highest at acidic conditions with an equilibration time of 25 min. The adsorption followed a Langmuir model, with an adsorption capacity of 303 mg g^?1, was second order in its kinetics, and exothermic and thus spontaneous.     

天然沸石对溶液中氨氮吸附特性的研究

为了探讨天然沸石对NH4 的吸附规律,以浙江缙云出产的粒径为2~3.2mm的天然斜发沸石为实验材料,进行吸附等温线实验和吸附动力学实验。结果表明,实验沸石对NH4 的吸附等温线符合Langmuir公式,且对氨氮吸附量的极限值为1.624mol·kg-1;实验沸石对NH4 的吸附反应符合一级动力学方程,反应速率常数为0.1882h-1。通过监测溶液中各阳离子浓度的变化,可确定沸石晶体内与NH4 进行交换的主要离子为Ca2 和Na ,二者占交换总量的96%以上;在交换反应初期,出现了由于沸石晶体中的离子在固液两相中的再分配所造成的离子交换的不等量现象。     

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293.35 μmol·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-1 NaOH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.     

锰氧化物-阳离子交换树脂复合材料的制备及其对水中重金属的吸附性能

采用原位沉淀-空气氧化法将锰氧化物负载于大孔强酸性阳离子交换树脂D001上,制备出一种新型锰氧化物-阳离子交换树脂复合材料Mn-D001,并对该材料吸附水中Pb2+、Cd2+、Cu2+的性能进行了深入研究.TEM、XRD以及XPS的分析结果表明,负载的锰氧化物以MnO2的形态存在.基于单一金属离子静态吸附的一元体系实验表明,Mn-D001比D001对Pb2+、Cd2+、Cu2+具有更高的吸附选择性,在高浓度竞争离子Ca2+、Mg2+、Na+共存的情况下,仍能保持较高的重金属去除率;Mn-D001对Pb2+、Cd2+、Cu2+的吸附行为符合准一级动力学模型(R2>0.99)和Langmuir吸附等温线模型(R2>0.99).在温度为303 K时,Mn-D001对3种重金属的饱和吸附容量可分别达到476.19 mg·g-1、243.90 mg·g-1及196.08 mg·g-1,优于原有树脂D001.基于复合重金属离子竞争吸附的二元、三元体系的实验表明,Mn-D001对3种重金属的吸附能力顺序为Pb2+>Cu2+>Cd2+,吸附能力由原有树脂D001以及负载的锰氧化物的性质共同决定.     

我国各地膨润土的水理特性

考察了我国各地膨润土的水理性质,讨论了膨润土的水理性质与层间阳离子的关系以及水理性质的矿床矿样间差异性,并对膨润土水理性质与其他物化性质间的相关性进行了分析。研究结果表明,膨润土因其属型和属性不同使其水理性质有较大的差异,其中层间阳离子类型是影响膨润土水理性质的重要因素,其中钠基膨润土具有高的胶质价、膨胀容和膨润值;不同矿床类型比较发现,沉积岩型矿样和火山沉积岩型矿样有较高的胶质价、膨胀容和膨润值;c轴有序度和<2 祄颗粒的质量分数与膨润土水理性质高度正相关。     

两种盐复合改性活性氧化铝对水中氟的吸附特性

采用Fe2(SO4)3和Al2(SO4)3两种盐对活性氧化铝进行改性,通过静态吸附实验,研究了改性活性氧化铝对水中氟离子的吸附特性及影响因素.改性后的活性氧化铝吸附容量显著提高,25 ℃下吸附容量达到6.25 mg·g-1.改性活性氧化铝对氟的吸附动力学符合拟二级动力学模型,吸附等温线更符合Langmuir等温吸附规律.吸附过程ΔG0H0 > 0、ΔS0 > 0,表明改性吸附剂对氟的吸附是自发的,是吸热、熵增加的反应.吸附最佳pH值为6,吸附过程中,共存PO43-对吸附效果影响最大.     

几种土壤的基本理化性质与Cu2+吸附的关系

研究了大冶市几种类型土壤的基本性质及与Cu2+吸附的关系,结果表明,土壤对Cu2+的吸附量随其CEC值(记为CEC)而变化,供试土壤的Cu2+吸附量由大到小的顺序为石灰土→水稻土→潮土→棕红壤.加入铜浓度为5 mmol·L-1时11个土壤对铜的吸附量x((mol·g-1)与CEC的直线相关方程为x(Cu2+) = 2.018×CEC + 24.4 (r=0.7066).而影响CEC的因素,如Ph、粘粒含量及其组成、有机质、比表面等,也是决定Cu2+吸附量的重要因素.     

Adsorptive removal and recovery of the azo dye Eriochrome Black T

Bottom ash and de-oiled soya have been evaluated as potential adsorbents for the removal of a water soluble azo dye. The characterization of the adsorbents has been performed using infrared spectroscopy and differential thermal analysis. A batch of adsorption method has been adopted for studying the effects of pH, adsorbate concentration, and particle size on the adsorption process. The experimental data were tested using Langmuir, Freundlich, Tempkin, and Dubinin–Radushkevich isotherms and their parameter constants were determined. The thermodynamics showed that the process is spontaneous and exothermic. The kinetic studies revealed that the adsorption process follows first-order kinetics. A fixed-bed adsorption experiment resulted in 89% and 94% saturation of bottom ash and de-oiled soya, respectively, indicating that both adsorbents can be potentially economical.     

改性加拿大一枝黄花去除水中Cr(Ⅵ)的特性分析

以生物入侵植物加拿大一枝黄花为原料,利用环氧氯丙烷、氢氧化钠和三乙胺对其进行化学改性,制备出含季铵基的吸附剂.采用元素分析、扫描电镜、X射线衍射、红外光谱、氮气吸附和X射线光电子能谱等手段对改性前后加拿大一枝黄花物理化学性质进行表征,并通过批实验的方法探讨了改性前后加拿大一枝黄花对Cr(Ⅵ)的吸附行为及热力学性质.结果表明,加拿大一枝黄花改性后纤维素内部产生了爆裂式膨胀,含氮量增加,引入了季铵基,吸附Cr(Ⅵ)离子能力显著提高.吸附实验结果表明,改性加拿大一枝黄花吸附去除Cr(Ⅵ)的平衡时间约为3 h,pH值为1—7范围内吸附效果较好.吸附过程符合准二级动力学模型,并均能较好地符合Langmuir和Freundlich等温吸附模型(R2> 0.95),298 K时最大吸附量为29.62 mg·g-1.应用van't Hoff 方程对吸附热力学参数进行了计算,结果表明Cr(Ⅵ)在改性加拿大一枝黄花上的吸附为熵加的自发物理吸热过程.     

Adsorption of caesium from aqueous solution using cerium molybdate–pan composite

In this study, a cerium molybdate–polyacrylonitrile (CM–PAN) composite ion exchanger was synthesised and its characteristics were determined by X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetry (TGA), specific area measurement (BET), X-ray fluorescence and CHN elemental analyses. The adsorption of caesium from aqueous solutions by CM–PAN composite was investigated under batch and continuous conditions. The distribution coefficient of caesium on the composite sorbent was studied as a function of pH, solution temperature and the presence of interfering cations, and the optimum conditions for a batch system were determined. Pseudo-first- and second-order sorption kinetic models were used to investigate the kinetics of adsorption and the results pointed to the pseudo-second-order model for caesium sorption kinetics. The intraparticle diffusion model was used to the predict rate-limiting step of the ion exchange process in order to specify the sorption mechanism. Langmuir, Freundlich and Dubinin–Radushkevich (D–R) isotherm models were fitted to the experimental sorption data, where the Freundlich model showed a good agreement. The adsorption thermodynamic parameters, standard enthalpy, entropy and Gibbs’ free energy were calculated and the reaction was found to be endothermic and spontaneous. Finally, the dynamic sorption capacities of the sorbent at two breakthroughs were calculated from the continuous system.     

钙基膨润土和钠基膨润土对Pu的吸附行为

通过静态吸附实验,探讨了在不同条件下,钙基膨润土和钠基膨润土对239Pu的吸附行为.结果表明,钙基膨润土对钚的吸附能力强于钠基膨润土;固液比的增大有助于膨润土对钚的吸附,但达到一定值后对吸附不再产生影响;两种膨润土的吸附能力均随着水相pH的增大而增强,但随着CO32-和Fe3+离子浓度的增大而减弱;此外,两种膨润土对Pu的吸附行为均可用Freundlich等温式表示.     

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.     

Pu在地下水溶液中的形态及吸附行为

以GMZ膨润土为吸附介质,纯水和阿拉善某地下水为溶液,研究了Pu在GMZ膨润土中的吸附平衡时间关系、Pu初始浓度与吸附量的关系、不同浓度pH值对Pu的吸附影响.用PHREEQC软件模拟计算了水溶液中Pu的形态.研究表明,实验条件下GMZ膨润土对Pu的吸附平衡时间为20 h,中性环境中吸附效果大于酸性环境中的吸附效果,纯水溶液中的吸附效果大于阿拉善某地下水溶液中的吸附效果,通过模拟形态分析,溶液中的形态对吸附效果产生一定影响,在酸性溶液中主要是Pu3+,中性溶液中主要是Pu（OH）3+,碱性溶液中主要是Pu（OH）4.