Magnetic nanocomposite of maize offal biomass for effective sequestration of Congo red and methyl orange dyes from contaminated water: modeling, kinetics and reusability

Abstract

The current study aims to use a facile and novel method to remove Congo red (CR) and Methyl Orange (MO) dyes from contaminated water with Maize offal biomass (MOB) and its nanocomposite with magnetic nanoparticles (MOB/MNPs). The MOB and MOB/MNPs were characterized with Fourier-transform infrared (FTIR), scanning electron microscopy (SEM), BET, XRD and point of zero charge (pH_PZC). The influence of initial CR and MO levels (20–320 mg/L), adsorbent dosage (1-3 g/L), pH (3-9), co-exiting ions, temperature (25–45 °C) and time (15–180 min) was estimated. The findings demonstrated that MOB/MNPs exhibited excellent adsorption of 114.75 and 29.0 mg/g for CR and MO dyes, respectively while MOB exhibited 81.35 and 23.02 mg/g adsorption for CR and MO dyes, respectively at optimum pH-5, and dose 2 g/L. Initially, there was rapid dye removal which slowed down until equilibrium was reached. The interfering/competing ions in contaminated water and elevated temperature favored the dyes sequestration. The MOB/MNPs exhibited tremendous reusability and stability. The dyes adsorption was spontaneous, and exothermic with enhanced randomness. The adsorption effects were well explained with Freundlich model, pseudo second order and Elovich models. It is concluded that MOB/MNPs showed excellent, eco-friendly, and cost-effective potential to decontaminate the water.

Graphical Abstract

HIGHLIGHTS

• Nanocomposite of Maize offal biomass demonstrated higher dyes removal.

• FTIR, SEM, BET, XRD and pH_PZC provided vital evidence for dyes adsorption.

• MOB/MNPs displayed excellent stability and reusability for dyes adsorption.

• Groundwater samples exposed a higher dyes removal.

• Results were validated with equilibrium and kinetic adsorption models.

Keywords:

• Adsorption
• dye sequestration
• kinetics
• modeling
• reusability
• stability

Acknowledgement

The authors extend their appreciation to the Researchers Supporting Project number (RSPD2023R725) King Saud University, Riyadh, Saud Arabia.

Author contributions

All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by [Muhammad Salman Tariq], [Muhaammad Imran] and [Salah Ud Din]. The first draft of the manuscript was written by [Muhammad Salman Tariq] and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.

Competing interests

The authors have no relevant financial or non-financial interests to disclose.

Additional information

Funding

The author Muhammad Imran is thankful to Higher Education Commission (HEC) of Pakistan under grand number 10377/Federal/NRPU.