Utilization of Pleurotus eryngii biosorbent as an environmental bioremedy for the decontamination of trace cadmium(II) ions from water system Farah Amin, Farah Naz Talpur, Aamna Balouch, Muhammad Kashif Samoon, Hassan Imran Afridi and Muhammad Ali Surhio ABSTRACT In many parts of the world, cadmium metal concentration in drinking water is higher than some international guideline values. To reduce its level below the safety limit, a sustainable and environmental friendly approach is crucial. Thereby, present article introduce an efficient, non- pathogenic and a novel fungal biosorbent Pleurotus eryngii for the removal of Cd(II) ions from aqueous system. The efficiency of P. eryngii were improved and optimized by investigating many significant factors such as; pH, biosorbent dose, initial Cd(II) ion concentration, temperature and contact time. Maximum Cd(II) ions removal (99.9%) was achieved at pH 5.0, biosorbent dosage 0.2 g/10 mL, concentration 20 mg L 1 , time 10 min and temperature 50  C. The isotherm and kinetic models revealed bioremediation of Cd(II) ions as monolayer coverage with biosorption capacity of 1.51 mg g 1 following pseudo second order reaction. Moreover, thermodynamic parameters such as ΔG  , ΔH  , and ΔS  showed that the removal of Cd(II) ions is spontaneous and endothermic in nature. Batch elution process revealed that the complete elution of Cd(II) ions from the biomass were achieved using 0.1 N HNO 3 solution. The sorption efficiency decreased from 99.99 to 56.89% as the biomass were recycled up to five times. The efficiency of Cd(II) ions removal from real water samples lies between 85 and 90%. Fourier transform infrared (FTIR) spectrometry, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopic (EDS) and atomic force microscopic (AFM) analysis of fungal biomass confirmed that the Cd(II) ions were the most abundant species on the biomass surface after the sorption process. Farah Amin Farah Naz Talpur (corresponding author) Aamna Balouch Hassan Imran Afridi Muhammad Ali Surhio National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, 76080, Pakistan E-mail: farahtalpur@hotmail.com Muhammad Kashif Samoon Centre for Pure and Applied Geology, University of Sindh, Jamshoro, 76080, Pakistan Key words | bioremediation, cadmium, isotherms, kinetics, Pleurotus eryngii, thermodynamics INTRODUCTION Cadmium is a toxic, non-essential heavy metal of consider- able environmental and occupational concern ( Jaishankar et al. ). It is released into the environment through com- bustion of fossil fuels, manufacturing of batteries, metal production, fertilizers, refining processes, electroplating, smelting, alloy industries, mining, pigments and screens (Ojedokun & Bello ). Its non-biodegradable property causes severe accumulation in living organisms with signifi- cant threats to the environment and public health (Gaur et al. ). Typically, the traces of cadmium ions in human body classified as carcinogen and teratogen impact- ing lungs, kidneys, liver and reproductive organs (Abdel- Shafy & Mansour ). According to the World Health Organization (WHO) standards, the maximum permissible limit of Cd(II) ions in drinking water is 3 ppb (0.003 mg L 1 )(WHO ). So far, the measured Cd(II) ion concentration in many regions is higher than that prescribed by the WHO. Hence, there is an urgent need to use low cost but sustainable technologies to remove this toxic metal from the aqueous environment. Consequently, several physico-chemical strategies for instance; filtration, chemical precipitation, electro-chemical treatment, oxidation/reduction, ion exchange, membrane technology, reverse osmosis and evaporation recovery have been developed for the removal of heavy metals, including Cd(II) ions from polluted water (Gao et al. ; 1148 © IWA Publishing 2018 Water Science & Technology | 78.5 | 2018 doi: 10.2166/wst.2018.365 Downloaded from http://iwaponline.com/wst/article-pdf/78/5/1148/494690/wst078051148.pdf by guest on 13 December 2021