Contents lists available at ScienceDirect Journal of Environmental Chemical Engineering journal homepage: www.elsevier.com/locate/jece The novel usage of dead biomass of green algae of Schizomeris leibleinii for biosorption of copper(II) from aqueous solutions: Equilibrium, kinetics and thermodynamics Mohammad Tavana a , Hassan Pahlavanzadeh a, *, Mohammad Javad Zarei b a Faculty of Chemical Engineering, Tarbiat Modares University, Tehran, Iran b Faculty of Advanced Technologies, NanoChemical Engineering Department, Shiraz University, Shiraz, Iran ARTICLE INFO Editor: Zhang Xiwang Keywords: Copper Schizomeris algae Biosorption Kinetics Thermodynamics ABSTRACT Copper ion Cu(II) as a toxic and carcinogenic component can be deposited in liver resulting in subsequent abdominal pain, respiratory problems, liver and kidney failure. According to US Environmental Protection Agency, the maximum Cu(II) should be below 1.3 mg/L in industrial effluents. Cu(II) must be removed from wastewaters before disposal. Dead green algae Schizomeris leibleinii, an abundant solid waste, was applied as a novel sorbent for Cu(II) removal from aqueous solutions. Experimental factors including initial pH, contact time, adsorbent dosage, initial copper concentration and temperature were studied. FTIR and FE-SEM/EDS analyses were performed before and after adsorption. The maximum adsorption capacity was 55.06 mg/g obtained at 700 mg/L in optimal condition of initial pH = 6, contact time = 60 min, 0.4 g adsorbent in 50 ml copper(II) solution and T = 25 °C. The maximum adsorption was obtained 96.71 % at initial concentration of 100 mg/L in a 3.5 h contact time. Three kinetic models of Morris-Weber, pseudo first-order and pseudo second-order were used and the pseudo second-order was the best fit with correlation coefficient of 1 compared to Morris-Weber and pseudo first-order models with correlation coefficients of 0.977 and 0.843, respectively. Freundlich and Langmuir isotherms were more precise for experimental data to describe the equilibrium of the adsorption. This proves the process is both physisorption and chemisorption. The thermodynamic analysis revealed the process of Cu(II) sorption on S. leibleinii was feasible, spontaneous and exothermic. Comparing the adsorption capacity of S. leibleinii to other adsorbents for Cu(II) removal shows this biosorption has potential for industrial applications. 1. Introduction Existence of heavy metals pollutants in water is known as a con- troversial issue due to toxicity of the food chain and non-biodegrad- ability in the environment and human body. Regarding World Health Organization (WHO), lead, copper, cadmium, cobalt, mercury, chro- mium, nickel and zinc existing in contaminated surface waters, groundwaters and industrial wastewaters are numerated as the metals of most immediate concern [1–6]. Copper is known as a vital trace element needed for its precious role in synthesis of enzyme, bone and tissues improvement in human bodies. Yet, copper ion (Cu(II)) is poi- sonous and carcinogenic and is deposited in the liver resulting in dis- astrous health problems. Based on the statistics of United States En- vironmental Protection Agency, the Cu(II) permissible limit is 1.3 mg/L in industrial effluents and WHO defines its permissible limit for Cu(II) equals to 1.5 mg/L for drinking water [7]. Water shortage in arid or semi-arid countries is a very important issue and toxic heavy metals must be captured from wastewater in a specific stage before disposal and polluting water resources and need to be treated for further use to avoid health hazards and water shortage. Several methods exist for heavy metal removal such as filtration [8], chemical precipitation [9], ion exchange [10], reverse osmosis [11], evaporating recovery [12], solvent extraction [13], adsorption [14], etc. All these techniques suffer from some demerits including in- complete removal, high reagent and energy consumption, generation of toxic sludge or other waste products. There is, therefore, a significant demand for some alternative methods, which are much more efficient and cost effective. Biomaterials possess supreme potential and cap- ability to remove heavy metals by biosorption process due to their abundance and their environmentally-friendly features as well as being cost effective and easy to use, although it is known as an adsorption process. Bisorption that can be considered as a modified adsorption https://doi.org/10.1016/j.jece.2020.104272 Received 18 May 2020; Received in revised form 2 July 2020; Accepted 9 July 2020 ⁎ Corresponding author at: Faculty of Chemical Engineering, Tarbiat Modares University, P. O. Box 14115-11, Tehran, Iran. E-mail address: pahlavzh@modares.ac.ir (H. Pahlavanzadeh). Journal of Environmental Chemical Engineering 8 (2020) 104272 Available online 15 July 2020 2213-3437/ © 2020 Elsevier Ltd. All rights reserved. T