Pineapple leaf (Ananas comosus) powder as a biosorbent for the removal of crystal violet from aqueous solution

Dyes are present in the industrial effluents which need to be treated before discharging to the environment as they pose severe environmental and health impacts. For this, biosorption has been considered as an economic and efficient technology as compared to the other treatment processes. Thus, biosorption characteristics of Ananas comosus (pineapple) leaf powder (PLP) was investigated for decolorization of crystal violet (CV), a cationic dye from its aqueous solutions employing a batch experimental setup. The parameter studied included contact time, initial dye concentration, adsorbent dose, pH, agitation speed, particle size of adsorbent, and temperature. Different isotherm models, Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin were found. Maximum adsorption was found with <150 μ particle sized 50 mg of PLP at 30°C with 200 rpm at pH 8. The maximum adsorption capacity (qm) was found to be 158.73 mg/g. Lagergen pseudo-second-order model best fits the kinetics of adsorption. Intra particle diffusion plot showed boundary layer effect and larger intercepts indicates greater contribution of surface sorption in rate-determining step. Adsorption of CV on adsorbents was found to increase on decreasing initial concentration, increasing pH up to 8, decreasing temperature, increasing agitation speed, and decreasing particle size. Overall, the present findings suggest that PLP is environmentally friendly, efficient, and low-cost biosorbent which is useful for the removal of CV from aqueous media.