Simultaneous removal of Zn(II) ions and pathogens from pharmaceutical wastewater using modified sugarcane bagasse as biosorbents

Abstract

Sugarcane bagasse (SCB) was developed into biosorbents by base (BSB), acid (ASB), and acid-base (A-BSB). The biosorbents were deployed to remediate pharmaceutical wastewater that was laden with Zn(II) ions and pathogens. The wastewater was characterised and revealed an increased Zn(II) ions concentration of 10.41 mg/l, total bacterial count (TBC) of 1.3 × 103 CFU/ml, and total coliform count (TCC) of 6 × 102 CFU/ml. These pollutants are hazardous to human and aquatic lives if discharged into the ecosystem without treatment. The developed biosorbents were characterised by FTIR, XRD, SEM with EDX mapping, and BET. The FTIR spectra showed peaks of the carboxylic groups present in lignin and hemicellulose which have good biosorbent properties. The XRD revealed the effect of the chemical modification of the SCB by changing the compound composition from sucrose to cellulose. The BET of the A-BSB gave the highest surface area and pore volume of 5.339 × 102 m2/g and 2.722 × 10−1 cc/g respectively, while the pore size of 2.105 nm was the lowest. Therefore, A-BSB exhibited optimum 99% removal of Zn(II) ions, and antimicrobial capacity of 100% removal for both TBC and TCC at 120 min, 40 °C, and 0.5 g dosage. The A-BSB is the most suitable adsorbent among the developed biosorbents for pharmaceutical wastewater treatment, as the findings from the kinetics study recommended chemisorption. Hence, the chemical modification of SCB was a promising low-cost adsorbent for Zn(II) ions and pathogens' removal from aqueous solutions.

Keywords

• Heavy metal
• Characterisation
• Biosorbents
• Cellulose
• Temperature
• Isotherm