Dilip H. Lataye

Rice husk ash as an effective adsorbent: Evaluation of adsorptive characteristics for Indigo Carmine dye

Present study explored the adsorptive characteristics of Indigo Carmine (IC) dye from aqueous solution onto rice husk ash (RHA). Batch experiments were carried out to determine the influence of parameters like initial pH (pH(0)), contact time (t), adsorbent dose (m) and initial concentration (C(0)) on the removal of IC. The optimum conditions were found to be: pH(0)=5.4, t=8h and m=10.0 g/l. The pseudo-second-order kinetic model represented the adsorption kinetics of IC on to RHA. Equilibrium isotherms were analyzed by Freundlich, Langmuir, Temkin and Redlich-Peterson models using a non-linear regression technique. Adsorption of IC on RHA was favorably influenced by an increase in the temperature of the operation. The positive values of the change in entropy (DeltaS(0)) and heat of adsorption (DeltaH(0)); and the negative value of change in Gibbs free energy (DeltaG(0)) indicate feasible and spontaneous adsorption of IC on to RHA.

Adsorption of Furfural from Aqueous Solution onto Activated Carbon: Kinetic, Equilibrium and Thermodynamic Study

Abstract The present study aims to evaluate the influence of various experimental parameters viz. initial pH (pH 0), adsorbent dose, contact time, initial concentration and temperature on the adsorptive removal of furfural from aqueous solution by commercial grade activated carbon (ACC). Optimum conditions for furfural removal were found to be pH 0 ≈ 5.9, adsorbent dose ≈ 10 g/l of solution and equilibrium time ≈ 6.0 h. The adsorption followed pseudo‐second‐order kinetics. The effective diffusion coefficient of furfural was of the order of 10−13 m2/s. Furfural adsorption onto ACC was found to be best represented by the Redlich‐Peterson isotherm. A decrease in the temperature of the operation favorably influenced the adsorption of furfural onto ACC. The positive values of the change in entropy (ΔS 0); and the negatived value of heat of adsorption (ΔH 0) and change in Gibbs free energy (ΔG 0) indicated feasible, exothermic, and spontaneous nature of furfural adsorption onto ACC.

Removal of fluoride from aqueous solution: status and techniques

Abstract Presence of various hazardous contaminants like fluoride, arsenic, nitrate, sulfate, pesticides, heavy metals, and other elements in ground water or surface water make the water unsafe and dangerous for the drinking purpose. The presence of any of these elements in drinking water in excess to the permissible limit is harmful for the human life. Fluoride is one of the elements which is very important for health especially for the children during teeth formation as well as harmful for human health if present in water more than permissible limit. Absence or insufficient amount of fluoride in drinking water causes dental caries during teeth formation of children whereas the presence of excess fluoride in drinking water causes dental and skeletal fluorosis. Therefore, maintaining of fluoride concentration within the safe limits is very important. The presence of excess fluoride in drinking water is a global problem. Excessive fluoride concentrations have been reported in ground waters of more than 27 ...

Removal of Fluoride from Aqueous Solution by Using Low-Cost Sugarcane Bagasse: Kinetic Study and Equilibrium Isotherm Analyses

AbstractIn the present study, sugarcane bagasse (Saccharum officinarum) was utilized to assess its capacity for the adsorption of fluoride from aqueous solutions. The batch adsorption experiments were carried out to calculate the adsorption capacity of sugarcane bagasse for the adsorption of fluoride from aqueous solution. The effects of various parameters like initial pH (pH0), adsorbent dose (m), contact time (t), initial concentration (C0), and temperature (T) on the adsorption of fluoride from the aqueous solution were studied. The adsorption rate is found to be very fast. For C0=4  mg/L, about 45% fluoride removal was found in t=60  min contact time at m=1  g/L adsorbent dose. The sorption kinetics could be well represented by a pseudosecond-order kinetic model. The minimum uptake of fluoride was found to be 1.20  mg/g, maximum uptake was observed to be 1.82  mg/g at lower concentration (4  mg/L). At higher concentration (8  mg/L), the minimum uptake of fluoride was found to be 2.50  mg/g and maximum...

Removal of 4-nitrophenol from aqueous solution by adsorption onto activated carbon prepared from Acacia glauca sawdust.

The present paper deals with a complete batch adsorption study of 4-nitrophenol (4NP) from aqueous solution onto activated carbon prepared from Acacia glauca sawdust (AGAC). The surface area of the adsorbent determined by methylene blue method is found to be 311.20 m(2)/g. The optimum dose of adsorbent was found to be 2 g/l with 4NP uptake of 25.93 mg/g. The equilibrium time was found to be 30 minutes with the percentage removal of 96.40 at the initial concentration of 50 ppm. The maximum removal of 98.94% was found to be at pH of 6. The equilibrium and kinetic study revealed that the Radke-Prausnitz isotherm and pseudo second order kinetics model fitted the respective data well. In the thermodynamic study, the negative value of Gibbs free energy change (-26.38 kJ/mol at 30°C) and enthalpy change (-6.12 kJ/mol) showed the spontaneous and exothermic nature of the adsorption process.

Adsorptive Removal of Phenol from Aqueous Solution Using Activated Carbon Prepared from Babul Sawdust

AbstractStudy on the adsorption of phenol onto activated carbon prepared from Babul (Acacia nilotica) sawdust (BAC), a waste from sawmill, is presented in this paper. The effect of various parameters such as adsorbent dose (m), initial pH (pH0), contact time (t), initial concentration (Co), and temperature (T) on adsorption capacity of BAC was tested using batch adsorption experiments. The kinetic study was performed by using different kinetic models, viz pseudo first, pseudo second order, and intraparticle diffusion. Langmuir, Freundlich, Redlich-Peterson, and Temkin isotherm equations were used to find the suitable and well-describing experimental isotherm data. The adsorption of phenol onto BAC follows the pseudo second order kinetic model, and equilibrium adsorption data follow the Redlich-Peterson and Freundlich isotherm equation. The maximum removal of phenol was found to be about 83% for the initial concentration of 50  mg/L and about 50% for the higher initial concentration of 500  mg/L at 10  kg/...

Neutralization of red mud with pickling waste liquor using Taguchi’s design of experimental methodology

‘Red mud’ or ‘bauxite residue’, a waste generated from alumina refinery is highly alkaline in nature with a pH of 10.5–12.5. Red mud poses serious environmental problems such as alkali seepage in ground water and alkaline dust generation. One of the options to make red mud less hazardous and environmentally benign is its neutralization with acid or an acidic waste. Hence, in the present study, neutralization of alkaline red mud was carried out using a highly acidic waste (pickling waste liquor). Pickling waste liquor is a mixture of strong acids used for descaling or cleaning the surfaces in steel making industry. The aim of the study was to look into the feasibility of neutralization process of the two wastes using Taguchi’s design of experimental methodology. This would make both the wastes less hazardous and safe for disposal. The effect of slurry solids, volume of pickling liquor, stirring time and temperature on the neutralization process were investigated. The analysis of variance (ANOVA) shows that the volume of the pickling liquor is the most significant parameter followed by quantity of red mud with 69.18% and 18.48% contribution each respectively. Under the optimized parameters, pH value of 7 can be achieved by mixing the two wastes. About 25–30% of the total soda from the red mud is being neutralized and alkalinity is getting reduced by 80–85%. Mineralogy and morphology of the neutralized red mud have also been studied. The data presented will be useful in view of environmental concern of red mud disposal.

Multicomponent Sorption of Pyridine and Its Derivatives from Aqueous Solution onto Rice Husk Ash and Granular Activated Carbon

The present paper deals with the simultaneous removal of Pyridine (Py), α -picoline ( αPi ) , and γ -picoline ( γPi ) from aqueous solutions by sorption onto rice husk ash (RHA) and granular activated carbon (GAC). Optimal design of experiments using Taguchi’s methodology has been applied to study the effects of various parameters, viz adsorbent dose, initial pH, contact time, initial concentrations, and temperature on the simultaneous removal of Py, αPi , and γPi . 313 orthogonal array of Taguchi design has been used for parameter optimization for the sorption ( qtot ) of Py, αPi and γPi , by RHA and GAC. The ANOVA shows that the initial concentration of αPi is the most significant parameter with 27.6% and 27.8% contribution to the qtot for raw and signal-to-noise (S/N) ratio data, respectively, for RHA. For GAC, the adsorbent dose (m) is the most significant parameter with 32.2% and 17.5% contribution to the qtot for raw and S/N ratio data, respectively. The interactions between initial concentrations a...

Adsorption of Indigo Carmine Dye onto Acacia Nilotica (Babool) Sawdust Activated Carbon

AbstractThe current study reports the utilization of Acacia nilotica (babool) sawdust activated carbon (AAC) for indigo carmine (IC) dye adsorption from aqueous medium. The surface area and surface...