Contents lists available at ScienceDirect Journal of Water Process Engineering journal homepage: www.elsevier.com/locate/jwpe Derived hybrid biosorbent for zinc(II) removal from aqueous solution by continuous-flow activated sludge system A.H. Jagaba a,b, *, S.R.M. Kutty a , S.G. Khaw a , C.L. Lai a , M.H. Isa c , L. Baloo a , I.M. Lawal b , S. Abubakar b , I. Umaru b , Z.U. Zango d a Department of Civil and Environmental Engineering, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, Perak Darul Ridzuan, Malaysia b Department of Civil Engineering, Abubakar Tafawa Balewa University, Bauchi, Nigeria c Universiti Teknologi Brunei, Brunei d Department of Fundamental and Applied Sciences, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, Perak Darul Ridzuan, Malaysia ARTICLE INFO Keywords: Activated sludge Biomass Bioreactor Derived hybrid biosorbent Zn(II) ions ABSTRACT Zinc ion is a toxic metal mostly contained in industrial effluents. To minimize its contamination levels due to the detrimental effect on both human health, environment and the eco-system, developing novel materials is es- sential for the removal of zinc ions. This study focused on the development and utilization of groundwater treatment plant sludge, microwave incinerated rice husk ash and derived hybrid biosorbent for the removal of zinc ions from aqueous solution. Standard methods were adopted for the preparation and characterization of the biosorbents and zinc aqueous solution. The biosorption experiments performed in batch systems at room tem- perature. Factors that may affect the zinc removal efficiency such as pH, reaction time, initial concentration, counter-ions, regeneration studies and substrate removal rate were investigated. Results indicated that the de- veloped biosorbents removed zinc concentration between 84–99 %. Removal efficiencies for derived hybrid biosorbent at different zinc concentrations were in the order 0.5 m/L > 1.0 mg/L > 5.0 mg/L > 2.0 mg/L > 10 mg/L > 15 mg/L. The effluent concentrations were between 0.01–3.52 mg/L, 0.01–1.27 mg/L, 0.01–2.31 mg/L and 0.01–2.01 mg/L for groundwater treatment plant sludge, microwave incinerated rice husk ash and derived hybrid biosorbent respectively. The biosorbents exhibited high affinity to zinc ion in the presence of competing ions. Biosorbents were regenerated into their initial functionality by HCl acid without significant capacity loss. Therefore, the biosorbents can be viable alternatives for efficient zinc removal because they are highly sensitive, selective and sustainable. 1. Introduction Portable water is a necessity for safeguarding the environmental ecosystem and human health. Recent trends in development within the industrial sector have greatly increased portable water demand for human activities. However, these industrial developments have led to the accumulation of diverse contaminants from industrial waste dis- charges. Thus, causing water pollution through heavy metal ions [1,2]. The neglect of wastewater disposal facilities and environmental reg- ulations in developing countries is another environmental problem by heavy metals [3]. Water contamination from heavy metals has gained significant attention due to its negative environmental effects and the prevailing health concerns [4]. In recent times, heavy metal con- tamination has become an increasingly serious global environmental problem that causes various diseases and disorders [5]. Heavy metals affect the environment, including human, animal and plant health, as they are harmful, carcinogenic, non-biodegradable and easily stored in living organisms [6]. Unlike microbial pollutants, heavy metals do not degrade. They can contaminate the soil and aquatic ecosystems [7]. They are lethal contaminants to the environment because, they highly affect water quality and pose a significant risk to the ecosystem and human health [8]. The presence of these toxic metal ions in water bodies is originated either by natural or anthropogenic origins. In- dustrial waste discharges have remained the major source of heavy metals [3]. Thus, compliance with permissible limits before discharging effluents into the environment becomes necessary. Heavy metals such as copper, mercury, zinc, cobalt, lead, chromium and cadmium have been causing severe environmental problems [1]. https://doi.org/10.1016/j.jwpe.2020.101152 Received 23 November 2019; Received in revised form 8 January 2020; Accepted 12 January 2020 ⁎ Corresponding author at: Department of Civil and Environmental Engineering, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, Perak Darul Ridzuan, Malaysia. E-mail address: ahmad_19001511@utp.edu.my (A.H. Jagaba). Journal of Water Process Engineering 34 (2020) 101152 2214-7144/ © 2020 Elsevier Ltd. All rights reserved. T