Otimizaçâo de um método alternativo para remoção de Pb2+ e Ba2+ de soluções aquosas, empregando fibra de coco como material biossorvente

This work presents the optimization of an alternative method for the removal of lead (Pb²⁺) and barium (Ba²⁺) from public supply water using coconut fiber as a biosorbent material. A system of four fixed-bed reactors connected in series, each with a volume of 0.250 L, was employed, operated in an upward continuous flow. A central composite rotational design (CCRD) was used, where the critical values that maximized the removal of Pb²⁺ ions were: pH = 4.8; time = 57.11 min; and biomass concentration = 25.45 g/L. For Ba²⁺ ions, the critical values were: pH = 4.99; time = 53.41 min; and biomass concentration = 19.83 g/L. The removal percentage was determined at the critical values, and an increase in lead removal (from 82% to 88%) and a reduction in barium removal (from 94% to 89.2%) were observed when using four reactors in series. In the multi-elemental analysis containing both lead and barium simultaneously and using the average values found for the ions analyzed separately (pH = 5.0; time = 55.26 min; biomass concentration = 22.64 g/L), there was a slight reduction in lead removal (from 81.2% to 78%), but within the standard deviation, and barium removal remained stable (92.6%). Thus, this alternative method proved to be promising for the removal of potentially toxic metals in public supply water.