Chromate transport through columns packed with surfactant-modified zeolite/zero valent iron pellets

Li, Zhaohui; Jones, H. Kirk; Zhang, Pengfei; Bowman, Robert S.

doi:10.1016/j.chemosphere.2007.03.011

Cited by 80 publications

(35 citation statements)

References 16 publications

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“…Chemical modification with inorganic salts (NaCl, CaCl2, BaCl2, NH4Cl, FeCl3) or a cationic surfactant (hexsadecyltri-methylammonium (HDTMA) -bromide) give to improve zeolite properties and increase its efficiency in water treatment [19,[31][32][33][34][35][36][37][38]. For successful modification high-concentration solutions of inorganic salts on the surface of zeolite is significant as shown in Figure 6.…”

Section: Modification With Solution Of Inorganic Saltsmentioning

confidence: 99%

Natural Zeolites in Water Treatment – How Effective is Their Use

Margeta¹,

Logar²,

Šiljeg³

et al. 2013

Water Treatment

174

150

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Additional information is available at the end of the chapter http://dx.doi.org/10.5772/50738 IntroductionNatural zeolites are environmentally and economically acceptable hydrated aluminosilicate materials with exceptional ion-exchange and sorption properties. Their effectiveness in different technological processes depends on their physical-chemical properties that are tightly connected to their geological deposits. The unique treedimensional porous structure gives natural zeolites various application possibilities. Because of the excess of the negative charge on the surface of zeolite, which results from isomorphic replacement of silicon by aluminum in the primary structural units, natural zeolites belong to the group of cationic exchangers. Numerous studies so far have confirmed their excellent performance on the removal of metal cations from wastewaters. However, zeolites can be chemically modified by inorganic salts or organic surfactants, which are adsorbed on the surface and lead to the generation of positively charged oxihydroxides or surfactant micelles, and which enables the zeolite to bind also anions, like arsenates or chromates, in stable or less stable complexes. Natural zeolites have advantages over other cation exchange materials such as commonly used organic resins, because they are cheap, they exhibit excellent selectivity for different cations at low temperatures, which is accompanied with a release of non-toxic exchangeable cations (K + , Na + , Ca 2+ and Mg 2+ ) to the environment, they are compact in size and they allow simple and cheap maintenance in the full-scale applications. The efficiency of water treatment by using natural and modified zeolites depends on the type and quantity of the used zeolite, the size distribution of zeolite particles, the initial concentration of contaminants (cation/anion), pH value of solution, ionic strength of solution, temperature, pressure, contact time of system zeolite/solution and the presence of other organic compounds and anions. For water treatment with natural zeolites, standard procedures are used, usually a procedure in column or batch process. Ion exchange and adsorption properties of natural zeolites in comparison with other chemical and biological processes have the advantage of Water Treatment 82removing impurities also at relatively low concentrations and allows conservation of water chemistry, if the treatment is carried out in the column process [1]. Subject of further academic and industrial research should be to improve the chemical and physical stability of modified zeolites and to explore their catalytic properties, which would allow their use in catalytic degradation of organic pollutants. More careful consideration of their superb metal removal properties and awareness of possible regeneration or further use of contaminant/metal-loaded forms can considerably increase their environmental application possibilities, with a focus the reduction of high concentrations of cations and anions in drinking water and wastewater, for surface, und...

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Section: Modification With Solution Of Inorganic Saltsmentioning

confidence: 99%

Natural Zeolites in Water Treatment – How Effective is Their Use

Margeta¹,

Logar²,

Šiljeg³

et al. 2013

Water Treatment

174

150

View full text Add to dashboard Cite

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“…These cationic surfactants increase the fractional organic carbon content in order to enhance the sorption of non-polar hydrophobic organic contaminants. It was observed that the longer the tail group of the cationic surfactant, the more stable the surfactant retained on the surface [3]. Chromium(VI) sorption was performed at different pH values.…”

Section: Modification Of Zeolites With Cationic Surfactantsmentioning

confidence: 99%

“…Likewise, to precipitate Cr(VI), it must first be reduced to Cr(III). The reduction of Cr(VI) is advantageous in itself because the trivalent form is a thousand times less toxic [3] and can be effectively adsorbed or precipitated.…”

Section: Introductionmentioning

confidence: 99%

A Review on Cr(VI) Adsorption Using Inorganic Materials

Rosales-Landeros¹,

Barrera-Díaz²,

Bilyeu³

et al. 2013

AJAC

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Chromium compounds are widely used in electroplating, metal finishing, magnetic tapes, pigments, leather tanning, wood protection and electronic and electrical equipment. Hexavalent chromium is a highly toxic metal and produces health damages. The most soluble, mobile and toxic forms of hexavalent chromium in soils are chromate and dichromate and the chromium distribution is also controlled by redox processes, its adsorption decreases with increasing pH and when competing dissolved anions are present. Several techniques have been developed to remove Cr(VI) from wastewater but these techniques have disadvantages such as high cost, non-selective, pH dependence, etc. The use of low cost sorbents has been investigated as a replacement for current costly methods; natural materials with a high adsorption capacity for heavy metals can be obtained. Modification of the sorbents can improve adsorption capacity. This paper includes some techniques for remove Cr(VI) with clays, silica and zeolites from aqueous solutions, some of the treated adsorbents show good adsorption capacities.

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“…Effect of рН on reactive blue 50 sorption: The pH is a very important parameter that affects dye sorption process on zero valent iron [9,12]. The sorption experiment was carried out for the removal of reactive blue 50 using zero valent iron in the pH range 2.0-12.0.…”

Section: Optimal Conditionmentioning

confidence: 99%

Study of the adsorption of reactive blue 50 on zero valent iron

et al. 2014

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In this study, removal efficiency of the Reactive blue 50 and adsorption mechanism on the zero valent iron were investigated. Reactive blue 50 which is used to wool and cashmere dyeing were selected due its non-biodegradable and metabolic stability. Zero valent iron particle has been synthesized by chemical method. A systematic characterization of zero valent iron was performed using X-ray diffractometer, scanning electron microscope and infrared spectrometer analysis. The optimal condition of adsorption was determined as initial reactive dye 50 concentration of 150 mg·L-1, zero valent iron mass of 0.2 g and solution pH of 6.0 at room temperature. At optimal condition, organic dye removal in a real wastewater sample from Tsombon Knit LLC was 99.5%.Mongolian Journal of Chemistry 15 (41), 2014, p21-26

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Chromate transport through columns packed with surfactant-modified zeolite/zero valent iron pellets

Cited by 80 publications

References 16 publications

Natural Zeolites in Water Treatment – How Effective is Their Use

Natural Zeolites in Water Treatment – How Effective is Their Use

A Review on Cr(VI) Adsorption Using Inorganic Materials

Study of the adsorption of reactive blue 50 on zero valent iron

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