Chromium biosorption from aqueous environments by mucilaginous seeds of Cydonia oblonga: Thermodynamic, equilibrium and kinetic studies

Abstract

Hexavalent chromium Cr(VI) is one of the most toxic heavy metals in aqueous solutions, hence it is highly imperative to treat the wastewater containing Cr(VI) before its discharge. At present work, the rate of biosorption was studied under a variety of conditions, including initial Cr(VI) concentration (5-50 mg/L), amount of biosorbent (0.5-3 g/100 mL), pH (1-8), temperature (298-318 K) and contact time (30-120 min). Biosorption of Cr(VI) is in all cases pHdependent showing a maximum at equilibrium pH values between 2 and 3. The biosorption data fitted well with Langmuir and Freundlich isotherms. The biosorption capacity calculated from the Langmuir isotherm was q = 33.58 mg Cr(VI)/g of dry seeds (at 303 K). Biosorption kinetics data well fitted using pseudo-second-order. Thermodynamic studies confirmed that biosorption of Cr(VI) ions by mucilaginous seeds of Cydonia oblonga was spontaneous and endothermic nature.

Process optimization and modeling of Cd2+ biosorption onto the free and immobilized Turbinaria ornata using Box–Behnken experimental design

“…As a result, the need for less expensive, safe, and more effective methods to remove heavy metals from wastewater has necessitated research into low-cost alternatives to currently existing techniques 7 . Numerous approaches have been considered for the removal of toxic heavy metals from wastewater, such as solvent extraction, reverse osmosis, adsorption, ion exchange, and chemical precipitation 8 , 9 .…”

Removal of Hexavalent Chromium from Aqueous Solutions Using Natural Zeolite Coated with Magnetic Nanoparticles: Optimization, Kinetics, and Equilibrium Studies

“…In this study, adsorption kinetic parameters were determined based on the contact time variation using PFO and PSO kinetic models. The nonlinear and linearized forms of PFO and PSO kinetic models are expressed as follows [15]: (11) ln q e − q t = ln q e − k 1 2.303 t , t q t = 1 q e 2 k 2 + t q e , …”

“…The World Health Organization (WHO) and Environmental Protection Agency (EPA) have set permissible limits for the discharge of heavy metals to reduce pollution of water bodies (Table 1). Accordingly, the permissible limit of Cr(VI) discharged to surface water is 0.10 mg/L, while it is 0.05 mg/L for drinking water which can be achieved through the proper treatment of the wastewater containing Cr(VI) before discharged to the environment [15].…”

Evidences for the augmented Cd(II) biosorption by Cd(II) resistant strain Candida tropicalis XTA1874 from contaminated aqueous medium

“…Various conventional removal methods have been practiced to remove cadmium and other heavy metals from contaminated water since a long time. The worth mentioning are chemical precipitation, reverse osmosis, adsorption, reverse osmosis, ion exchange and other physico-chemical methods 16 , 17 . With time these methods have become outdated and suffer from severe drawbacks including high operational costs, continual monitoring, inefficiency in toxicant removal from dilute solutions and generation of toxic sludge 18 – 20 .…”