Bioengineering of iron oxide nanoparticles using leaves extract of Dalbergia sissoo for the removal of diclofenac and tetracycline from water: optimization by BBD approach.

Pharmaceutical compounds like tetracycline and diclofenac are causing significant environmental pollution, posing health risks and necessitating effective techniques for their elimination from water-based ecosystems. This study explores the potential of green-synthesized iron oxide nanoparticles (Fe₂O₃) in the adsorption of tetracycline (TC) and diclofenac (DF) and optimized the process using the Box-Behnken Design (BBD) approach. The average particle size of the synthesized Fe₂O₃ was found 15.71 nm. The BET results revealed that surface area, pore volume, and average pore diameter was 13.16 m²/g, 3.18 cm³/g, and 21.48 nm, respectively. At optimal conditions, TC and DF removal were 88.2-90.51%, respectively. with desirability function one. The Langmuir maximum adsorption capacity was 56.68 mg/g for TC and 62.36 mg/g for DF. The primary rate-limiting step is proposed to be chemisorption. The thermodynamics results confirm adsorption onto Fe₂O₃ that occurs spontaneously, endothermically, and randomly. The green Fe₂O₃ nanoparticles efficiently absorbed TC and DF from aqueous solutions upto five cycles, with efficiency declined from 87.9 to 67.23% and 90.01 to 65.23%, respectively, which showed economic applicability of materials. This study illustrates the efficacy of green-synthesized Fe₂O₃ nanoparticles in eliminating pharmaceutical pollutants and their significance in promoting sustainable water treatment technologies in accordance with circular economy and SDG objectives.