FLUORIDE REMOVAL FROM AQUEOUS SOLUTION BY ALMOND SHELL ACTIVATED CARBON

Fluoride (F-), the ion of the element fluorine, is one of the mineral elements present in nature that enters drinking water through underground aquifers and when present in high concentration it can lead to risks such as skeletal, dental, and non-skeletal fluorosis with morbidity such as decreased IQ and negative effects on brain development, tooth discolouration, and bone pain. The aim of the study, was to study the ability of activated carbon developed from almond shell (ACAS), to remove fluoride from an aqueous solution. We examined the effects on fluoride removal efficiency of contact time, initial F - concentration, pH, and ACAS mass. The equilibrium data were also examined with models including the Langmuir, Freundlich, and Temkin isotherms. The removal characteristics were validated through the use of different kinetic models for the estimation of the solute interaction and the nature of the biosorption. A contact time of 60 min, an adsorbent dosage of 0.6 g/L, and a pH of 3 were considered to be the optimal operational conditions. The biosorption of F- onto ACAS and the equilibrium data follow from the Langmuir adsorption isotherm with a maximum adsorption of 84.3 mg/g and a regression coefficient of R-2 =0.999. The kinetic studies showed that the system fitted the pseudo-second order kinetic model. Thus, this work gives new insights on the interaction of ACAS with F- in a reconstituted aqueous solution.