Brinjal <i>(Solanum melongena)</i> stalk waste as an effective scavenger for Eriochrome Black-T from water and wastewater: an approach towards waste to best
Amisha Rout, Md. Atif Qaiyum, Priyanka Priyadarsini Samal, Subhashri Dutta, Banashree Dey, Soumen Dey
Abstract
Stalks of brinjal (Solanum melongena), hereinafter SM, have been exercised as an efficient and sustainable adsorbent material for the elimination of Eriochrome Black-T (EBT) from an aqueous solution. The material was characterized by FTIR, FESEM, BET surface area, pHpzc, and proximate analysis. FTIR spectrum suggests the presence of polyphenolic moieties, responsible for successful dye binding. FESEM images show an unprecedented octopus-like texture containing micropores. The central head transforms the architecture of a flower. The evaluated BET surface area of 10.042 m2/g and pore volume 1.055 × 10−2 cm3/g suggest a porous material. The pHpzc of the material was evaluated to be 7.05, and under optimized conditions, the maximum adsorption capacity was found 52.631 mg/g at pH 7. The operational parameters were studied concerning contact time (0–90 min), pH (5–11), initial concentration (10–40 mg/L), and interfering ions (PO4−3, AsO4−3, Hg+2, Pb+2). Adsorption follows Langmuir isotherm best (R2 = 0.996), and pseudo-second-order kinetics (R2 = 0.991) indicate a monolayer and homogeneous adsorption. 83% regeneration was successful with 0.1(M) sodium hydroxide solution. The material can be reused for up to three cycles with 90% efficiency retention. Analysis of EBT containing industrial effluent indicates that 52.62% of EBT can be removed.