Kinetics of Cr(VI) Adsorption on Used Black Tea Leaves

Hossain, Mohammad Abul; Kumita, Mikio; Michigami, Yoshimasa; Mori, Susumu

doi:10.1252/jcej.38.402

Cited by 54 publications

(35 citation statements)

References 18 publications

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“…In conclusion, the maximum adsorption capacities of Cr(VI) were 42.46 mg/g and 42.42 mg/g using STL and AC, respectively. Another extensive study carried out by Rafie (2012) [17] focused [110] to evaluate the applicability of black STL as an adsorbent for the removal of Cr(VI) from aqueous solution in a batch mode experiment. They found that the adsorption of Cr(VI) occurred rapidly in the first 24 hr; then was followed by a slow process that required more than 10 days to reach its equilibrium.…”

Section: Spent Tea Leaves As Effective Sorbentsmentioning

confidence: 99%

Low-cost Adsorbents Derived from Agricultural By-products/Wastes for Enhancing Contaminant Uptakes from Wastewater: A Review

Sulyman

Namieśnik

Gierak

2017

Pol. J. Environ. Stud.

187

112

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A major threat to the comfort of human life has been imposed by increased industrialization and urbanization. The generation and disposal of huge amounts of toxic materials and pollutants have heavily contaminated our environment. Some Organics such as synthetic dyes (SD) and heavy metals (HM) are becoming increasingly prevalent as the most dangerous pollutants in soil and surface water environments. They are causing great concern worldwide due to their toxicity to many life forms.Environmentally friendly utilization of agricultural by-products/waste materials either as raw materials or in production of so-called activated carbons (AC) is an important issue. Because it is apparent from our literature review that the main factors characterizing these materials are their affordability, local availability, and efficiencies in removing many unwanted toxics and pollutants, they therefore could be utilized instead of more conventional but expensive adsorbent materials, particularly in developing countries where many industries lack appropriate individual sewage treatment systems; even where they exist, they lack satisfactory functioning and maintenance because of the lack of good budgets.A number of case studies are supplied in this review. These case studies have pointed to the efficient removal of SD/HM ions from aqueous solutions by the agricultural by-products/wastes in the form of a raw material, signifying spent tea leaves (STL) as a good example. Besides, the efficient removal of such ions by AC produced from these agricultural by-products/wastes has also been given in detail, suggesting a variety of AC agricultural by-products/wastes sources. Both kinds are widely used adsorbents in the treatment of wastewaters. Our review has shown that these adsorbents are characterized by many exceptional physical and chemical features that make them widely used adsorbents in the treatment of wastewaters. The adsorption efficiencies by these substances were also affected by the characteristics of AC, which depend on the physical and chemical properties of the precursor (i.e., agricultural by-products/wastes) as well as on the activation method applied, which is either chemical or physical. The structural properties of the resulting

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Section: Spent Tea Leaves As Effective Sorbentsmentioning

confidence: 99%

Low-cost Adsorbents Derived from Agricultural By-products/Wastes for Enhancing Contaminant Uptakes from Wastewater: A Review

Sulyman

Namieśnik

Gierak

2017

Pol. J. Environ. Stud.

187

112

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“…As the pH decreased from 4.4 to 2, the adsorption capacity increased from 3 mg/g to 25.2 mg/g; under basic conditions at pH 10, the adsorption of Cr(VI) ions decreased to 1.2 mg/g. In order to understand the mechanism of adsorption on CRH5M, the experimental data for various concentrations of Cr(VI) was fit into several kinetic models, including first-order (Hossain et al 2005), pseudo-first-order (Annadurai et al 2002), second-order (Sparks 1989), and pseudo-second-order models (Rengaraj et al 2003) (Fig. 8).…”

Section: Fig 3 Ft-ir Spectrum Of Crh and Crh 5mmentioning

confidence: 99%

Alkali-treated Carbonized Rice Husk for the Removal of Aqueous Cr(VI)

et al. 2016

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Rice husk was chemically modified for the preparation of activated carbon. Rice husk was treated with nitric acid and carbonized at 700 C. After carbonization, the resulting rice husk char was treated with NaOH at room temperature. The 5 M NaOH-treated rice husk had the highest surface area (750 m 2 /g). Proximate analysis of activated carbon confirmed that NaOH treatment removed silica completely. Temperature programmed decomposition (TPD) graphs showed that the total gas contents (CO and CO2) liberated by CRH and H2O-treated CRH and CRH5M were 2l5 μmol/g, 390 μmol/g, and 970 μmol/g, respectively. The adsorption studies of the activated carbon during Cr(VI) removal from the aqueous medium indicated that CRH5M showed the highest rate of adsorption. The effect of adsorbent dosage, Cr(VI) concentration, pH, and temperature were studied to determine the best removal efficiency. With a decrease in pH from 4.4 to 2, the adsorption capacity increased from 3 mg/g to 25.2 mg/g. The adsorption of Cr(VI) followed pseudo-second-order behaviour. The changes in Gibbs free energy, enthalpy, and entropy affected by thermodynamic parameters were found to be negative, which confirmed that the adsorption of Cr(VI) on CRH5M is spontaneous, exothermic, and favours low temperatures.

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“…Several kinds of low cost adsorbents such as buffing dust of leather industry [4], coconut husk [5], wheat bran [6], vetiver roots [7], date stones [8][9], pistachio nut shell [10], apple promace and wheat straw [11] were studied to evaluate their applicability for the removal of dyes from aqueous solutions by adsorption process. In recent year, high adsorption capacity of used black tea leaves (UBTL) as a low cost adsorbent to Cr(VI) [12][13][14] and dyes [15][16][17][18][19][20] were reported.…”

Section: Introductionmentioning

confidence: 99%

Equilibrium, Thermodynamic and Mechanism Studies of Malachite Green Adsorption on Used Black Tea Leaves from Acidic Solution

Hossain

Hassan

2016

ILCPA

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Abstract. This study reports the equilibrium adsorption mechanism and thermodynamics for the removal of Malachite Green (MG) from acidic solution using Used Black Tea Leaves (UBTL) as a low cost adsorbent. The effect of initial dye concentration, processing temperature and the presence of electrolytes on the adsorption from acidic solutions were investigated in batch process. Adsorption process was attained to the equilibrium at about 24 hours. Adsorption isotherms of MG on UBTL for different temperatures were constructed at pH 2.0 and the equilibrium adsorption data were analyzed using different model equations such as Langmuir, Freundlich, Temkin, DubininRadushkevich (D-R), Harkin-Jura, Halsey, Elovich-Larionov and Flory-Huggens isotherms. The experimental results were reasonably correlated by Langmuir, Flory-Huggins and D-R models than other isotherm models. The maximum adsorption capacity (q m ), intensity of adsorption (b) and separation factor (R b ) were calculated from Langmuir plot and activation energy of adsorption (E ad ) was determined from D-R isotherm. At pH 2.0, the equilibrium adsorption capacity of UBTL to MG is 110 mg•g -1 at 30°C, which was increased with increasing temperature suggested endothermic nature of adsorption. Thermodynamics parameters: ΔG ads , ΔH ads and ΔS ads were calculated from Langmuir constant (b). The positive values of enthalpy and free energy, and negative value of entropy suggested that the adsorption is less spontaneous and surface migration or fragmentation of MG molecules on UBTL surface might be occur. Again, the low value of activation energy of adsorption (E ad = 0.3 kJ•mol -1 <8 kJ•mol -1 ) suggested that the adsorption is controlled by physical in nature. A possible mechanism involvement of protonation is proposed from the effect of electrolytes during the adsorption of MG on UBTL at pH 2.0.

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Kinetics of Cr(VI) Adsorption on Used Black Tea Leaves

Cited by 54 publications

References 18 publications

Low-cost Adsorbents Derived from Agricultural By-products/Wastes for Enhancing Contaminant Uptakes from Wastewater: A Review

Low-cost Adsorbents Derived from Agricultural By-products/Wastes for Enhancing Contaminant Uptakes from Wastewater: A Review

Alkali-treated Carbonized Rice Husk for the Removal of Aqueous Cr(VI)

Equilibrium, Thermodynamic and Mechanism Studies of Malachite Green Adsorption on Used Black Tea Leaves from Acidic Solution

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