Sorption properties of modified peat with respect to petroleum and heavy metals

The group composition of high-moor peat modified by mechanical activation was studied, and the physicochemical characteristics of this peat were determined. It was found that the preliminary mechanical activation of peat, in particular, in the presence of iron oxyhydoxide improved its characteristics as a sorbent for petroleum and heavy metals.     

改性氧化石墨烯对废水中重金属的吸附

简述了石墨烯的基本结构以及氧化石墨烯在结构上的优越性。概述了氧化石墨烯的主要改性方法。针对不同的影响因素,总结了改性氧化石墨烯对废水中重金属的吸附效果。对去除水体中重金属的反应机理进行了归纳,指出了改性氧化石墨烯目前应用在污水处理中存在的问题及应用前景。     

改性玉米淀粉对重金属捕集性能的研究

研究了二硫代氨基甲酸改性玉米淀粉(DTCS)对单一重金属溶液中重金属离子的捕集作用,考察了影响其捕集作用的因素,包括重金属种类、pH、温度、混凝时间、无机离子的干扰等,确定了合适的应用条件.结果表明,在单一重金属离子浓度为1.0×10-3 mol/L的溶液中,DTCS对重金属离子捕集的选择性:Cu2 ＞Pb2 ＞Cd2 ＞Zn2 ＞Ni2 ,去除率分别为99.91%、99.88%、87.36%、85.17%、66.36%,且K 、Ca2 等无机离子对其去除效果影响不大.     

钠基膨润土对重金属离子的吸附特征

探讨了在不同振荡时间、不同溶液重金属离子浓度、不同矿物颗粒细度和不同pH值条件下,钠基膨润土对Cu2+、Zn2+和Cd2+的吸附效果,讨论了钠基膨润土对重金属离子吸附的影响因素。结果表明:重金属离子在钠基膨润土表面的吸附是个迅速的过程,钠基膨润土对重金属的吸附在10 min内即可达最大值。钠基膨润土不同颗粒细度对重金属离子的去除率有所不同,但并非颗粒越细吸附量越大。就试验的3种重金属离子而言,钠基膨润土对其吸附效果均很好。较高的pH值有助于钠基膨润土对溶液中重金属离子的吸附,但考虑到实际操作的其它因素,不能把pH值调得过高。     

泥炭吸附法去除废水中重金属

介绍了天然廉价矿物泥炭的物理化学性质,综述了泥炭的改性方法及其对多种重金属离子的吸附容量．分析了pH、改性方法、竞争离子浓度等因素的影响。并对泥炭吸附重金属离子的机理和规律进行了总结．其吸附机理有离子交换、络合、表面吸附、化学吸附等四种,吸附一般符合Langmuir吸附等温式或Freundlich吸附等温式。最后展望了泥炭在重金属废水处理中的应用前景,提出了一些建议。     

Adsorption of heavy metals by brewery biomass

In this work, biosorption of lead, copper and cadmium by waste brewery yeast has been studied. The adsorption capacity for lead, copper and cadmium on the biomass increased with the increasing temperature and the maximum uptakes were 0.465 mmolPb/g (96.4 mg/g), 0.769 mmolCu/g (48.9 mg/g) and 0.127 mmolCd/g (14.3 mg/g) at 308 K. The Langmuir isotherm, favorable type, and the pseudo second-order kinetic model represent our experimental data very well. The heat of biosorption was evaluated from the Langmuir isotherm equation, and the biosorption of lead, copper and cadmium was endothermic reaction.     

Adsorption of heavy metals and methylene blue from aqueous solution with citric acid modified peach stone

Peach stones (PS) modified by citric acid (MPS) were used to remove heavy metals and methylene blue (MB) from wastewater. The effects of experimental factors such as pH, adsorbent dosage and contact time, etc. were conducted. Moreover, the adsorption kinetics and isotherm studies also were investigated. According to the Langmuir isotherm model, the maximum adsorption capacities of Pb²⁺, Cd²⁺, Cu²⁺ and MB were 118.76, 37.48, 32.22 and 178.25 mg/g, respectively. Finally, column experiments were also carried out to investigate the adsorption of Pb²⁺ and MB. All results indicated that PS has a good potential for the treatment of wastewater.     

Adsorption equilibrium of heavy metals on natural zeolites

Prior to equilibrium experiments, a clinoptilolite-type Korean natural zeolite was pretreated with HCl, NaOH, and NaCl to improve the ion-exchange capacity for heavy metals. Singleand multi-species equilibrium data of heavy metals such as copper, cadmium, cesium, and lead on treated and untreated natural zeolites were measured experimentally. For single-species equilibrium data, one of the conventional adsorption isotherms, the Sips equation, was used to fit them and then multi-species equilibrium data were predicted by using the loading ratio correlation (LRC), the ideal adsorbed solution (IAS) theory, and the real adsorbed solution (RAS) theory based on the Sips equation. In applying the RAS theory, we used the Wilson equation for fitting activity coefficients of metal ions in the ion-exchanger phase. It was proven that basic adsorption models except the LRC model could describe multi-species ion-exchange equilibrium for heavy metals/natural zeolite systems well.     

Adsorption of heavy metals by pirymidine-derivated mesoporous hybrid material

This paper describes the synthesis of pyrimidine-derivated hybrid mesoporous material via chemical bonding. This has been done by modifying the silanol groups of the support with a synthesised pyrimidine propyl triethoxysilane. The hybrid material has been characterized by X-ray diffraction, nitrogen adsorption techniques, FT-IR, ²⁹Si and ¹³C MAS NMR. The potential of the material of removing heavy metal as copper, nickel and cobalt from water has been tested. Effects of pH, velocity of adsorption, selectivity, maximum adsorption capacity and preconcentration capacity have been determined.     

Adsorption of selected toxic metals by modified peanut shells

The objective of this study was to modify peanut shells to enhance their adsorptive properties toward the metal ions cadmium (Cd²⁺), copper (Cu²⁺), nickel (Ni²⁺), lead (Pb²⁺) and zinc (Zn²⁺). Milled peanut shells were initially washed with water or 0.1 N NaOH or left unwashed. Following these treatments or lack of treatment, the shells were either left unmodified or modified by a heat treatment in the presence of either 1.0 M phosphoric acid or 0.6 M citric acid. Modified peanut shells were evaluated either for adsorption efficiency or for adsorption capacity using the five metal ions listed above. Adsorption efficiencies and capacities were compared with efficiencies and/or capacities for the commercial chelating or cation exchange resins Amberlite 200, Amberlite IRC‐718, Duolite GT‐73, and carboxymethylcellulose. For the adsorption efficiencies of individual metal ions, modified peanut shells met or exceeded the adsorption values for cadmium, copper, nickel or zinc ions compared with the commercial resins Duolite GT‐73 and carboxymethylcellulose. In a solution containing all five metal ions, modified peanut shells met or exceeded the adsorption efficiencies for cadmium, copper and lead ions compared with Duolite GT‐73, Amberlite IRC‐718 and carboxymethylcellulose. Adsorption capacities of modified peanut shells met or exceeded the adsorption capacity of Duolite GT‐73 for lead ions only. Citric or phosphoric acid‐modified peanut shells showed a preference for Cu²⁺ and Pb²⁺ and appear promising as potentially inexpensive adsorbents for selected metal ions. © 2001 Society of Chemical Industry     

有机改性蒙脱土对农药敌草隆的吸附研究

以十六烷基三甲基溴化铵(CTAB)有机改性蒙脱土为吸附剂,采用静态摇瓶试验,研究了改性蒙脱土对除草剂敌草隆的吸附行为.探讨了温度、离子强度、腐殖酸、溶液pH值对敌草隆吸附的影响.试验结果表明,CTAB改性蒙脱土对敌草隆具有较大的吸附容量,最大吸附量为20.31 mg/g吸附等温线可用Freundllich方程来描述;吸...     

Adsorption of multicomponent volatile organic compounds on semi-coke

Experimental and theoretical studies were made on the adsorption of toluene, ethyl acetate, benzene and their binary and ternary mixtures by semi-coke in an isothermal condition of 293 K. Breakthrough curves of these volatile organic compounds (VOCs) were measured by a gas chromatograph. The results showed that the adsorptive orders of these three VOCs were: toluene > ethyl acetate > benzene. The phenomenon of “roll-up” was observed in the breakthrough curves and under this condition, the more strongly adsorbed species displace the weaker ones. H₂O₂ was used to activate the semi-coke and the activation enhanced the adsorption capacity of semi-coke to all the three VOCs, especially to toluene. The extended Langmuir equation agrees well with the experimental isotherm data for binary and ternary mixtures and the error is below 5%.     

Influence of organic sulfur compounds and metals on mesophase formation

The influence of organic sulfur compounds and metals on the texture of the mesophase formed in pitch during the carbonization process was investigated by the addition of organic sulfur compounds and organometallic compounds to the cracked oil obtained from Khafji asphalt and polyvinyl chloride (PVC) pitch. These pitches, containing sulfur and metals, have been examined by polarised light microscopy, and quinoline insolubles (QI), sulfur and metal contents were determined. The existence of either organic sulfur compounds or organometallic compounds in the pitch has no effect on mesophase texture. However, the coexistence of sulfur and metals (such as vanadium or nickel) has a great effect on mesophase texture. From these results, sulfur and metals coexisting in the pitch have a catalytic effect which activates the thermal decomposition and the thermal polymerization reactions of the pitch. Furthermore, the precursors of mesophase (β resin) are formed abundantly in the pitch by these reactions. These precursors promote the nucleation of mesophase spherules, and a large number of mesophase spherules are formed in the pitch at the same time. Therefore, these spherules coalesce with each other before growing to large spheres and lead to a fine mosaic texture.     

石墨烯材料在重金属废水吸附净化中的应用

石墨烯材料具有较大的比表面积、良好的化学稳定性,近年来在环境污染物深度吸附处理方面的应用逐渐引起了人们的关注。本文综述了石墨烯材料在重金属离子的吸附处理方面的研究进展,包括普通石墨烯、氧化石墨烯、功能化石墨烯以及石墨烯复合物等材料;讨论了石墨烯表面功能化修饰对重金属离子吸附性能的影响;分析了各种材料的优点与缺点;提出了需进一步研究的问题,如石墨烯表面功能化修饰的结构-性能关系、石墨烯材料的循环使用以及石墨烯材料对痕量重金属离子的富集灵敏度等问题,指出合成选择性好、富集灵敏度高且可多次循环使用的石墨烯材料,在重金属废水的深度处理中将得到进一步应用。     

改性煤气化灰渣吸附重金属离子的研究

以煤气化灰渣为原料,采用酸改性法(HF酸)制备改性煤气化灰渣。通过静态实验研究了改性煤气化灰渣对溶液中Pb~(2+)、Cu~(2+)、Cd~(2+)的吸附特性,测定了溶液pH值、吸附时间、金属离子初始浓度对吸附的影响。结果表明,二级动力学方程很好的描述溶液中重金属离子在改性煤气化灰渣上的吸附过程;吸附等温线符合Langmuir模型,Pb~(2+)、Cu~(2+)、Cd~(2+)的静态饱和吸附量分别为112.07,40.18,31.21 mg/g。     

改性煤气化灰渣吸附重金属离子的研究

以煤气化灰渣为原料,采用酸改性法(HF酸)制备改性煤气化灰渣。通过静态实验研究了改性煤气化灰渣对溶液中Pb⁽²⁺⁾、Cu(2+)、Cu⁽²⁺⁾、Cd(2+)、Cd⁽²⁺⁾的吸附特性,测定了溶液pH值、吸附时间、金属离子初始浓度对吸附的影响。结果表明,二级动力学方程很好的描述溶液中重金属离子在改性煤气化灰渣上的吸附过程;吸附等温线符合Langmuir模型,Pb(2+)的吸附特性,测定了溶液pH值、吸附时间、金属离子初始浓度对吸附的影响。结果表明,二级动力学方程很好的描述溶液中重金属离子在改性煤气化灰渣上的吸附过程;吸附等温线符合Langmuir模型,Pb⁽²⁺⁾、Cu(2+)、Cu⁽²⁺⁾、Cd(2+)、Cd⁽²⁺⁾的静态饱和吸附量分别为112.07,40.18,31.21 mg/g。     

锂皂石有机改性研究进展

介绍了锂皂石水热法人工合成方法,并对锂皂石有机改性的实验手段、吸附机理和反应行为等研究现状进行了综述.锂皂石有机改性主要方法有原位法和吸附法.采用原位法改性时,许多有机物起模板作用,微晶在球状网孔内聚集老化.采用吸附法改性时,有机阳离子以离子交换和分配作用模式与锂皂石复合,非离子型有机物以物理吸附,分配作用,氢键作用等模式与其复合.锂皂石有机改性后,吸附性能、分散性及比表面积等提高.该领域正朝制备功能超分子材料方向迅速发展.     

Adsorption behaviors and mechanism of heavy metals onto attapulgite functionalized by polyamine silane

Pollution from heavy-metal ions has become a major challenge to the global fight against environmental pollution. Given the availability of various low-cost and environmentally friendly adsorbents, adsorption has become the most efficient technology for the removal of heavy metals from water. In this study, attapulgite (ATP) was directly functionalized by coupling with an aminosilane agent. Analysis showed this maneuver provided a suitable adsorbent for the removal of lead ion (Pb²⁺) from an aqueous solution. The effects of several parameters including solution pH, contacting time, adsorbent dosage, and initial Pb²⁺ ion concentration were investigated. Batch sorption results showed that the adsorption process was rapid and over 98% of Pb²⁺ was removed within 30 min at the optimal pH 4.0. The maximum adsorption capacity at 25°C, calculated by the Langmuir isotherm, was 82.17, 78.80, 61.13, and 28.56 mg/g for γ-divinyltriaminepropyl-methyldimethoxylsilane-grafted attapulgite (KH-103-ATP), γ-aminopropyl-methyldiethoxysilane-grafted attapulgite (KH-912-ATP), N-(β-aminoethyl-γ-aminopropyl)-methyl-dimethoxysilane-grafted attapulgite (KH-602-ATP), and ATP, respectively. Moreover, molecular dynamics simulations of adsorption behaviors of heavy-metal ions at attapulgite surfaces (010) modified by aminosilane agents were carried out. Both the PMF value and diffusion coefficient of metal ions suggest that KH-103-ATP owns the highest rate constant and capacity compared with the other two. And the analysis of free energy and results of XPS characterization revealed that Pb²⁺ formed covalent bonds with the nitrogen atom of aminosilane agents.     

Adsorption characteristics of construction waste for heavy metals from urban stormwater runoff☆

Stormwater runoff has become an important source of surface water pollution. Bioretention, a low impact devel-opment measure in urban stormwater management, has been proven to be effective in the removal of pol utants from stormwater runoff, with appropriate bioretention media. In this study, construction wastes were selected as bioretention media to remove heavy metals from stormwater runoff. Static and dynamic adsorption batch exper-iments were carried out to investigate the adsorption of heavy metals in simulated stormwater runoff system with construction wastes in different particle sizes. The experimental results show that the pseudo-second-order kinetic model characterizes the adsorption process and the adsorption equilibrium data are wel described by Freundlich isotherm model. The construction wastes used can remove heavy metals from stormwater runoff effectively, with their average removal rates al more than 90%. The particle size of construction wastes greatly influences the equilibrium time, rate and adsorption capacity for heavy metals.