Adsorption studies on fruits of Gular (Ficus glomerata): Removal of Cr(VI) from synthetic wastewater
ABSTRACT The adsorption of Cr(VI) was studied in batch system using fruits of Ficus glomerata as adsorbent. The effect of temperature, pH, initial Cr(VI) concentration and time was investigated. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) was used to investigate surface morphology and active functional groups present on the adsorbent surface. Thermodynamic parameters like free energy change (DeltaG(0)), enthalpy (DeltaH(0)) and entropy (DeltaS(0)) indicate the spontaneous, endothermic and increased randomness nature of Cr(VI) adsorption. Equilibrium data were fitted well with Langmuir isotherm at 50 degrees C. The magnitude of mean free energy indicates chemical nature of adsorption. The breakthrough and exhaustive capacities were found to be 5 and 23.1 mg g(-1) respectively. The applicability of the adsorbent has been demonstrated by removing Cr(VI) from electroplating wastewater.
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ABSTRACT: Fruit peel of Litchi chinensis showed remarkable adsorption capacity towards Cr(VI) ions. The effect of temperature, pH, initial Cr(VI) concentration and time was investigated using batch process. The adsorption of Cr(VI) was maximum at pH 2. Fourier transform infrared spectroscopy (FTIR) was used to explore number and position of active functional groups available for the binding of Cr(VI) ions. Thermodynamic parameters like change in standard free energy (ΔG °), enthalpy (ΔH °) and entropy (ΔS °) indicated the spontaneous, endothermic and increased randomness nature of Cr(VI) adsorption. Equilibrium data were well fitted in Langmuir isotherm at 40°C.The value of mean free energy (E = 8.28 kJ mol−1) indicated that adsorption process was chemical in nature. The breakthrough and exhaustive capacities were found to be 30 and 50 mg g−1 respectively. The results indicated that the adsorbent could be used effectively for the removal of Cr(VI) from electroplating wastewater by batch process.Desalination and water treatment 11/2012; 49(1-3):136-146. DOI:10.1080/19443994.2012.708211 · 0.99 Impact Factor
Article: Agricultural WastesWater Environment Research 10/2011; 83(10-10):1439-1466. DOI:10.2175/106143011X13075599869614 · 1.00 Impact Factor
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ABSTRACT: Watermelon rind (WR) an agro waste was evaluated as an adsorbent for the removal of Cr3+ ions from aqueous solution. Batch mode adsorption studies were performed by varying parameters such as pH, contact time, adsorbent dose and initial metal ion concentration. Maximum loading capacity of WR was found to be 172.6 mg g−1 for Cr3+ ions at pH 3. Kinetic studies show that removal of Cr3+ ions is rapid and follows a pseudosecond order model. Equilibrium data fit better with the Langmuir isotherm than the Freundlich isotherm. Thermodynamic parameters such as ΔG°, ΔH° and ΔS° were derived for the current system. The negative values of ΔG° show that the nature of sorption process is spontaneous. FTIR studies reveal that hydroxyl and carboxyl groups were responsible for uptake of metal ions. Successive desorption of Cr3+ ions reveals that WR can be an economical sorbent for the removal of heavy metals from aqueous solution. The results conclude that watermelon rind an agro waste can effectively be used for the removal of chromium ions from aqueous solution.AEJ - Alexandria Engineering Journal 08/2014; DOI:10.1016/j.aej.2014.07.006