RESPONSE SURFACE METHODOLOGY APPLIED TO THE OPTIMIZATION OF GREEN COCONUT (Cocos nucifera L.) WATER MICROFILTRATION PROCESS

Fruit juices are becoming more popular and viable as an alternative for traditional drinks like soda, coffee, and teas. Brazil is the fourth largest coconut producer in the world and the first in coconut water production. This makes researches in the fields of industrialization and development of coconut water products essential for the expansion of this market. This work aimed to optimize the clarification process of green coconut water (Cocos nucifera L.) in multichannel silicon carbide (SiC) membranes with a 0.175 m² filter area. Response surface methodology was applied in the tangential microfiltration parameters. For this, two central composite facecentered designs (CCF) were developed for membranes of 0.3µ and 0.6µ pore diameter. Pressure (50.125 and 200KPa) and temperature (20, 30 and 40°C) were the independent variables. Permeate flux (L.h-1.m-2) and fouling index (%) corresponded to the dependent variables. The significance level used was p<0.05, and a total of 11 experiments were performed on each design, all of them in recirculation mode (FRV=1). Optimum parameters for the 0.3µ pore diameter membrane were 82KPa and 30°C, with a predicted flow of 800 ± 35.77 L.h-1.m-2 and fouling index of 81.89 ± 0.82%. For the 0.6µ pore diameter membrane, 50KPa / 40°C was the optimal point, predicting the flow of 1263.34 ± 35.99 L.h-1.m-2 and fouling index of 84.33 ± 0.74%. All coefficients of determination (R2) for the designs were greater than 90%. These optimal data was used as a parameter for concentration mode microfiltration experiments (FRV>1). Increasing FRV processes showed average flow reduction of 50%, as expected, and the fouling indexes in all experiments were higher than 96%, meaning almost total clogging of the pores. It is concluded that the optimization of the clarification process was efficient, and the technical feasibility enables the possibility of expansion from pilot-scale to industrial.