Ultrasonic Assisted Removal of Methyl Paraben on Ultrasonically Synthesized Zn(OH)2-NPs-AC: Experimental Design Methodology

Abstract

Zn(OH)2 nanoparticles (Zn(OH)2-NPs) were sonochemically synthesized. Very low amount of Zn(OH)2-NPs was loaded on activated carbon with weight ratio of 1:10 followed by the characterization using FT-IR, XRD and SEM. Zn(OH)2 nanoparticle-loaded activated carbon (Zn(OH)2-NP-AC) as safe, green and cost-effective adsorbents were used for the removal of methyl paraben (MP). Also, the impacts of variables including initial MP dye concentration (X1), pH (X2), adsorbent dosage (X3), sonication time (X4) came under scrutiny using central composite design (CCD) under response surface methodology (RSM). The experiments have been designed utilizing response surface methodology. In this current article the values of 12 mgL-1, 0.03 g, 7.0, 4.0 min were considered as the ideal values for MP dye concentration, adsorbent mass, pH value and contact time respectively. The rapid adsorption process at neutral pH using very small amount of the adsorbent makes it promising for the wastewater treatment applications. More than 99.5% of methyl paraben was removed with maximum adsorption capacities 100 mgg−1 for MP. The kinetics and isotherm studies showed that the second-order and Langmuir models apply for the kinetics and isotherm of the adsorption of MP dye on the adsorbent used here. The adsorbent was shown to be well regenerable for several times. The short-time adsorption process, high adsorption capacity and the well regenerability of the safe, green and cost-effective Zn(OH)2-NP-AC make it advantageous and promising for the aqueous solutions.