ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Magnetite graphene oxide-doped superadsorbent hydrogel for efficient removal of crystal violet from wastewater

Sher Ali Khan, Tanzil Ur Rehman, Luqman Ali Shah, and Mohib Ullah

Polymer Laboratory, National Centre of Excellence in Physical Chemistry, University of Peshawar, Peshawar, Pakistan

E-mail: luqman_alisha@yahoo.com

Received: 6 June 2022  Accepted: 2 January 2023

Abstract:

A smart and novel magnetite graphene oxide-doped superabsorbent hydrogel (MGO-SAH) consisting of magnetite graphene oxide (MGO), acrylamide (AAm), acrylic acid (AAc), and 2-acrylamido-2-propane sulphonic acid (AMPS) were synthesized through free radical addition polymerization at temperature > 55 °C in oven for one hour. The hydrogel successfully employed for crystal violet (CV) removal from model wastewater. Various characterization techniques such as FT-IR and SEM were used for as synthesized hydrogel. The FT-IR data show the establishment of interaction and distribution of MGO within the 3D network of hydrogels and interaction with CV during removal process. The removal capability of the MGO-SAH superabsorbent hydrogel toward the crystal violet was elucidated while using the batch adsorption mechanism. The removal performance of MGO-SAH hydrogel was investigated by applying various parameters, such as contact time, dye initial concentration, sample dosage and thermos-dynamical approach. The % removal of the CV was monitored from the model solution via UV/Vis 1100 spectrophotometer. The kinetic study was performed by using the pseudo first and pseudo second order kinetic models. It was found that the kinetics of the materials follow pseudo second order kinetic model. The study showed that the % removal increases with increasing the sample dosage which is due to the increase in the number of active sites and diffusion capability of hydrogels. However, the % removal decrease for increasing in the concentration of dyes for constant weight sample (0.1 g) of the as synthesized materials due to insufficient viability of active sites for adsorption process. The adsorption efficiency of MGO-SAH was 88.78 mg g⁻¹ with percent removal value of 97%. In addition, some thermos-dynamical variables such as ∆G°, ∆H°, and ∆S° were calculated and the negative value found for ∆G° confirms the spontaneity of the process. A negligible decrease in efficiency was recorded in the recycling performance of the given hydrogel system.

Graphical abstract

Keywords: Crosslinked polymer; Adsorption; Dyes removal; Kinetics; Water treatment

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-023-02662-1

Chemical Papers 77 (5) 2725–2735 (2023)