The present work is focused on the effect of temperature on extraction of gallic acid using Aliquat 336, tri-n-butyl phosphate and tri-n-octylamine in hexanol and octanol. Distribution coefficient, loading ratio, percent extraction, equilibrium complexation constant, water coextraction, enthalpy, and entropy change were evaluated for various acid−extractant− diluent combinations with varying temperature. The extraction of GA was found to be highly exothermic at lower molality of TBP in octanol with evaluated enthalpy change as −28 743 J/mol. The extraction of gallic acid process was favored at low temperature as the process was evaluated as an exothermic in nature. Maximum extraction efficiency of 97.3% was observed at higher molality of Aliquat 336 in hexanol at lower temperature.

Gallic acid is a major phenolic pollutant present in the wastewater generated from cork boiling, olive mill, and pharmaceutical industries. Experimental and statistical modelling using response surface methodology (RSM) and artificial neural network (ANN) were carried out for reactive separation of gallic acid from aqueous stream using tri-nbutyl phosphate (TBP) in hexanol. TBP has a more significant effect on extraction efficiency as compared to temperature and pH. The optimum conditions of 2.34 g L -1 , 65.65 % v/v, 19 o C, and 1.8 of initial concentration of gallic acid, concentration of TBP, temperature, and pH, respectively, were obtained using RSM. Under optimum conditions, extraction efficiency of 99.45 % was obtained for gallic acid. The ANN and RSM results were compared with experimental unseen data. Error analysis suggested the better performance of ANN for extraction efficiency predictions.

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Reactive extraction of gallic acid (GA) from aqueous solution was studied using extractant TOA and Aliquat 336 in hexanol and a comparative analysis were made for optimum extractant-diluent system with two factor central composite design. The model equations were developed using 13 experimentations, each with TOA and Aliquat 336. TOA and Aliquat 336 gave antagonistic and synergistic effects respectively for extraction of GA. The optimum conditions were observed as CTOA= 8.6 %, CGA0= 2.9 g/L and CALQ= 33.2 %, CGA0= 3 g/L with experimental extraction of 92.2 % and 96.5 % respectively. Lesser TOA and its non-toxicity for extraction of GA as compared to Aliquat 336 suggest TOA as better candidate in the prevailing conditions.

Reactive crystallization of calcium oxalate has been studied to determine particle size distribution for calcium oxalate precipitation using population balance model with method of moments. The model is formulated and tested for single feed semi-batch reactive crystallization of calcium oxalate with reactants calcium chloride and sodium oxalate with literature data. The simulated results include local supersaturation distribution, number of particle distribution, mass of particle crystallized, particle size, nucleation and growth rate during the process. The model results are in good agreement with available experimental data from literature.