Good Sorption Capacity Research Articles

Adsorption of heavy metal ions on composite materials prepared by modification of natural silica

Recently because of increasing of environmental consciousness and demands, several discussions about the preservation of natural resources have led to more efforts concerning materials of good selectivity and high sorption capacity [1]. We have developed new composite materials with improved adsorptive properties thanks to the presence of Algerian silica (Kieselgiiter) [2], after undergoing suitable treatments. We have investigated the effect of different amounts of silica on the performance and adsorptive behaviour of the resulting composites. Thus, the work herein describes our investigations on the adsorption of heavy metal ions onto the composite materials from aqueous solutions in relation to different variables, such as shaking time, concentration of metal ions and pH. The adsorption behaviour of the concerned material is explained on the basis of its chemical nature and porous texture.

Packed-Bed Removal of Copper and Zinc Ions Using Chemically-Treated Chicken Feathers

In this work, the sorption of copper by chemically treated chicken feathers was tested via packed-bed column. Chicken feathers were selected as adsorbent based on its high availability as environmental waste. The alkaline-treated chicken feathers column showed good sorption capacity toward copper and zinc ions. It was proved that an increase in metal concentration or flow rate of the influent solution shortens the break-through time. The break-through time increased with the bed depth. The break-through time occurred earlier when zinc was passed through the column rather than copper, but the bed capacity was higher for the later than for the former. The key process design parameters, which could serve as a basis for sorption process scale up, were calculated by applying the Bed-Depth-Service-Time (BDST) model to the experimental data.

Synthesis of chelating resins with iminodiacetic acid and its wastewater treatment application

AbstractThe chelating resins have high potential applications for the selective removal and recovery of metal ions from industrial waste solutions. The hydrophilic acrylate monomer with the iminodiacetic acid chelating group was prepared from glycidyl methacrylate and iminodiacetic acid at 60°C. The microbeads, prepared from acrylate monomer with the iminodiacetic acid chelating group, were employed by inversion suspension polymerization. In the pH range of 2–6, a reasonably good equilibrium sorption capacity is maintained for Cr3+ (ca. 2.7 mmol/g) and Cu2+ (ca. 1.8 mmol/g) in the chelating resins. The adsorption of Cd2+ and Pb2+ on microbeads is clearly affected by the pH of the solution, such that these ions' adsorption capacity increased with the pH of the aqueous solution. The adsorption of Cd2+ (ca. 1.25–1.87 mmol/g) and Pb2+ (ca. 0.99–1.89 mmol/g) showed a maximum at approximately pH = 5 and 6, respectively. The adsorption isotherms of Cr3+ and Cu2+ adsorbed on microbeads were following the Langmuir isotherm, but the adsorption behavior of Cd2+ and Pb2+ were not. The concentration of alkaline earth–metal cations on the range of 0–200 ppm had no influence on metal ions adsorbed capacity of chelating resins. Additionally, NTA (nitrilotriacetic acid) had no significant influence on metal ion adsorption by chelating resins. Furthermore, phenol pollutant can be adsorbed effectively by metal ions chelated microbeads; therefore, the microbeads were useful not only in recovering metal ions but also in the treating phenol pollutants in wastewater. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1353–1362, 2002; DOI 10.1002/app.10243

Determination of distribution coefficient of 137Cs and 90Sr in soil from AERE, Savar

The sorption characteristics of 137Cs and 90Sr on soil matrix have been studied by the batch technique. The sorption coefficients ( K d ) and retardation factor ( R f ) have been determined for these radionuclides on soil matrices collected from a number of locations in and around the proposed site for shallow land disposal of low-level radioactive wastes at the Atomic Energy Research Establishment (AERE) campus, Savar. The K d values varied from 1278 to 2156 ml/g for 137Cs and from 350 to 640 ml/g for 90Sr. The retardation factors varied from 1709 to 3072 for 137Cs and from 409 to 903 for 90Sr. The results obtained indicated that the AERE soils have good sorption capacity for 137Cs and 90Sr radionuclides. These data could be used in radionuclides transport and safety assessment models.

Experimental Study and Modelling of the Interaction between U(VI) and the Surface of Iron(II)-Rich Olivine

Iron(II)-rich olivine has been proposed as an additive to the buffer material placed in high level radioactive waste final repository [1] due, both to its reducing capacity given by its content in iron(II) as well as to its ability to sorb heavy metals and radionuclides. Preliminary results have shown a good sorption capacity of the olivine [2,3]. In this work, a systematic study of the uranium (VI) sorption onto the olivine has been undertaken as a function of pH and the olivine mass.

Removal of Organic Pollutants by the Use of Iron(III) Hydroxide-Loaded Marble

Abstract Iron(III) hydroxide-loaded marble (Fe-marble) was studied as an adsorbent to remove phenolic compounds from aqueous solution. The coordination of ligands with the central metal ion occurs through the phenolic oxygen. Sorption and break-through capacities were determined. The effects of pH and concentration were studied. Adsorption remains unaffected in the 2–6 pH range. Fe-marble exhibits good sorption capacities for phenolic compounds, and the adsorption data follow the Langmuir model as well as the Freundlich model. Some experiments were also performed with a view to recovery phenols and create in-situ regeneration of spent adsorbent column. The phenols adsorbed were quantitatively eluted with 1 M NaOH solution. The column can be used for 4–5 cycles consecutively.

Modified hardwickia binata bark for adsorption of mercury (II) from water

Hardwickia binata bark was found to have a good sorption capacity for mercury (II). Colour leaching can be prevented and the physical characteristics of the bark can be improved by treatment with formaldehyde in acidic medium. Studies indicated that the sorption of Hg(II) increases as the pH increases and a contact time of 2 h was found to be optimum. The effect of concentration shows that modified bark can remove most of the Hg(II) from water if its concentration is below 20 mg/l and sorption of mercury conformed to the Freundlich adsorption isotherm. The presence of light metal ions interferes with the sorption of mercury. Mg(II) at a concentration of 200 mg/l interferes with sorption to a maximum extent. Among the different anions, it was observed that sorption of mercury was maximum for acetate and nitrate (97%). The break-through sorption capacity determined by conducting a column experiment was observed to be 21 mg/g.

Evaluation of polichrom a for preconcentration of volatile organic compounds from the atmosphere

The breakthrough volumes for vapours of 16 volatile organic compounds, including six organosulphur compounds, on 1,4-di(methacryloyloxymethyl)naphthalene-divinylbenzene (DMN-DVB) copolymers (Polichrom A) were determined using an indirect method based on extrapolation of the log VB=f(Tt-1) dependence to 20°. The sorbents examined differed with respect to the mole fraction of the polar component (DMN). The studies revealed very good sorption capacity of the examined sorbents, particularly the most polar one, compared with other commonly employed porous polymers which, taking into account the high thermal stability of DMN-DVB copolymers (up to 330°C), makes them suitable for preconcentration of volatile organic compounds from the atmosphere.

Evaluation of Polichrom A for preconcentration of volatile organic compounds from the atmosphere

The breakthrough volumes for vapours of 16 volatile organic compounds, including six organosulphur compounds, on 1,4-di(methacryloyloxymethyl)naphthalene-divinylbenzene (DMN-DVB) copolymers (Polichrom A) were determined using an indirect method based on extrapolation of the log VB=f(T−1) dependence to 20°. The sorbents examined differed with respect to the mole fraction of the polar component (DMN). The studies revealed very good sorption capacity of the examined sorbents, particularly the most polar one, compared with other commonly employed porous polymers which, taking into account the high thermal stability of DMN-DVB copolymers (up to 330°C), makes them suitable for preconcentration of volatile organic compounds from the atmosphere.

Studies on the efficiency of a local fertilizer waste as a low cost adsorbent

Waste slurry, generated in local fertilizer plants, is converted into activated carbon in air, steam and nitrogen atmospheres. Products so obtained have been characterized and utilized for the removal of phenols, especially 2,4-dinitrophenol. Investigations include the effect of pH, kinetics of adsorption and the effect of salts on the uptake of DNP. Carbon prepared in air exhibits good sorption capacity for DNP and the adsorption data follows both Langmuir and Freundlich models. Some experiments have also been performed with a view to recover phenols and have in situ regeneration of spent carbon column. It is observed that 5% NaOH removes almost 96% of phenol loaded on the carbon column and a treatment with 1 M HNO 3 reactivates the adsorbent particles which can be used for 6–10 cycles at a stretch.

Synthesis of anion exchangers with large-size pores

Styrene-divinylbenzene matrices with large-size pores have been prepared using a mixture of diluents (polystyrene, M w = 1.3–3.54 × 10 5 , and gasoline, b.p. 110–150°C) as porogenic agents. The macromolecular networks have been chloromethylated and subsequently aminated with trimethylamine in order to prepare anion exchangers with supermacroporous structure. The average pore radius of the networks is in the range of 40,000–250,000 Å and the pore volume is around 1.0 ml/g dry resin. The anion-exchange capacity is between 3.00 and 4.00 meq/g. Several of the anion exchanger samples have shown a good sorption capacity for colloidal silica (24.21 g SiO 2/l with an output of 99.80% by comparing with a commercial anion exchanger).