NOPR Collection:

Synthesis of polymeric chelating ligands from sago starch for metal removal from electroplating wastewater

Wed, 01 Jan 2014 00:00:00 GMT

Title: Synthesis of polymeric chelating ligands from sago starch for metal removal from electroplating wastewater Authors: Rahman, Md Lutfor; Yusoff, Mashitah Mohd; Malek, Muhammad Nor Fazli Abd; Samah, Nurlin Abu Abstract: Polymeric chelating ligands containing hydroxamic acid and amidoxime ligands have been synthesized from poly(methyl acrylate-co-acrylonitrile) grafted sago starch. Batch adsorption has been performed to identify the binding property of metal ions. Maximum sorption capacity of copper is found to be 2.80 mmol g^-1, however other transition metals has good sorption capacity with this ligands. The rate of exchange of some metals is found to be fast, i.e. t_½ 6 min (average). Three types of wastewater containing chromium, zinc, nickel, copper, and iron have been used in this study. The metal recovery is found to be high, and more than 99% of the metals could be removed from the metal plating wastewater. Polymeric chelating ligands could be used to remove the metals from wastewater. Page(s): 30-37

Evaluation of polymer-agglomerated granular tri-calcium phosphate for fluoride removal from drinking water

Wed, 01 Jan 2014 00:00:00 GMT

Title: Evaluation of polymer-agglomerated granular tri-calcium phosphate for fluoride removal from drinking water Authors: Sivasankari, C; Arulanantham, A Abstract: The powder and granular forms of tri-calcium phosphate have been used as adsorbents in batch studies for removal of fluoride from aqueous synthetic fluoride solutions. The effects of different operational parameters like pH, adsorbent dose, and contact time have been studied for their optimization. Results show that the fluoride removal is maximum and nearly constant in the pH range 3.0-8.0. The efficiency of fluoride removal increases with the increase in adsorbent dose and contact time. Surface morphology of the adsorbent has been examined with the scanning electron microscope. Experimental equilibrium adsorption data obtained is found to be fitted well with both Langmuir and Freundlich isotherm models. Adsorption kinetic study reveals that the adsorption process follows pseudo second – order kinetics. Column experiments are performed using granular tri-calcium phosphate (GTCP) to find out the optimum flow rate, bed height and the effect of co-existing anions in water. The optimum fluoride removal capacity in column study is found to be 2.1005 mg of fluoride per gram of GTCP. Regeneration of the adsorbent for repeated use has also been studied in column operation and it is established that complete regeneration could be achieved with 0.5% aluminium sulphate solution for 8 cycles without loss of efficiency. Page(s): 70-77

Self sustained autogenous dissolution of medium grade manganese ore of Gujarat in NH₃OHCl-H₂SO₄-H₂O medium

Wed, 01 Jan 2014 00:00:00 GMT

Title: Self sustained autogenous dissolution of medium grade manganese ore of Gujarat in NH₃OHCl-H₂SO₄-H₂O medium Authors: Hariprasad, D; Mohapatra, M; Rao, K Srinivasa; Anand, S Abstract: Leaching studies have been carried for dissolution of manganese from medium grade manganese ore in hydroxyl ammine hydrochloride-sulphuric acid medium. Due to exothermic nature of reaction no external heat is required for quantitative extraction of manganese confirming the self sustained autogenous nature of leaching process. Initially, the effects of individual parameters including time, sulphuric acid concentration, amount of reductant, pulp density, and particle size have been studied. One parameter has been changed at a time while keeping the other parameters constant. Per cent manganese extraction is found to be dependent on acid concentration and amount of reductant. Within 20 min, manganese could be quantitatively dissolved. A comparison of FTIR spectra of synthetic solution with actual leach solution indicates the formation of ClO₄^- ions during leaching. The XRD pattern of the residue shows only quartz as the crystalline phase. Response surface methodology is adopted applying a central composite design for 2⁴ factorial set of experiments. A statistical analysis is done to evaluate interactive effects. Using the model, optimised parameters in the range of pulp density 25 - 35 % wt /v, acid concentration 6.5-7.5% v/v, amount of reductant 15-16 g and time 10 - 30 min have been considered for maximum desirability. The experimental data is found to be fitted well with the predicted ones. Page(s): 63-69

Kinetic modelling of Fe³⁺ ion uptake by zeolite from water

Wed, 01 Jan 2014 00:00:00 GMT

Title: Kinetic modelling of Fe³⁺ ion uptake by zeolite from water Authors: Ćurković, L; Bolanča, T; Šiljeg, M; Foglar, L Abstract: The ability of the natural clinoptilolite (Cp), and its Na–enriched form (Na–Cp) to remove iron ions from acid aqueous solutions has been investigated in the batch system at the initial concentration of 100 mg Fe³⁺/L, pH value of 1.90, and the equilibration time of 30–300 min. In order to establish the Fe³⁺ uptake behaviour, the rate controlling step of the process and to determine the coefficients, the ion exchange kinetics have been investigated and the different models usually applied are used for description of adsorption kinetics. The Fe³⁺ uptake by Cp and Na-Cp is evaluated based on the first–order kinetics, modified Freundlich and Elovich models, parabolic diffusion and heterogeneous diffusion models. Developed models can successfully describe the ion exchange processes between Fe³⁺:Cp and Fe³⁺:Na–Cp. In addition, the results show that the natural Croatian clinoptilolite enables efficient removal of iron from water. Page(s): 56-62

NOPR Collection:

Synthesis of polymeric chelating ligands from sago starch for metal removal from electroplating wastewater

Evaluation of polymer-agglomerated granular tri-calcium phosphate for fluoride removal from drinking water

Self sustained autogenous dissolution of medium grade manganese ore of Gujarat in NH3OHCl-H2SO4-H2O medium

Kinetic modelling of Fe3+ ion uptake by zeolite from water

Self sustained autogenous dissolution of medium grade manganese ore of Gujarat in NH₃OHCl-H₂SO₄-H₂O medium

Kinetic modelling of Fe³⁺ ion uptake by zeolite from water