Activated and Nonactivated Date Pits Adsorbents for the Removal of Copper(II) and Cadmium(II) from Aqueous Solutions

Abstract

The present study aims to investigate the adsorption behavior of Cu(II) and Cd(II) ions from wastewater onto low-cost adsorbents either raw date pits (RDP), cheap agricultural and nontoxic materials, or chemically activated carbon (ADP) prepared by modified date pits using phosphoric acid. A series of experiments were conducted in a batch system to evaluate the effect of system variables. The adsorption process is affected by various parameters such as solution pH, contact time, initial concentrations of metals, and adsorbent dose. The optimum pH required for maximum adsorption was found to be 5.8 ± 0.5. The experimental data were tested using Langmuir, Freundlich, Dubinin-Radushkevich (D-R) isotherm equations. It was observed that the adsorption capacity of date pits increased after treatment with phosphoric acid. The maximum uptake capacities (Q m ) were 7.40 and 33.44 mg copper(II) per gram of RDP and ADP, respectively, while 6.02 and 17.24 mg cadmium(II) per gram of RDP and ADP, respectively. The results showed that although the equilibrium data could be described by the three models used, Langmuir model gave slightly better results while Freundlich model gave better results when using raw and activated date pits.

Removal of Heavy Metals from Wastewater using Date Palm as a Biosorbent: A Comparative Review

“…The sorption of Cu 2+ was rapid, with equilibrium reached within 120 min (Bouhamed et al 2012). The maximum adsorption was observed at pH 5.8±0.5 with activated date pits, which was five times more efficient than the raw date pits (Hilal et al 2012). The authors have also studied the application of both the raw and modified DP waste to study and compare the adsorption of Cu 2+ and the results are presented in the following sections (Amin et al 2016).…”

“…Similarly, the adsorption of Cd 2+ on to DP trunk fiber, AC derived from date stones and both the raw and chemically activated date pits was studied in batch tests of different parameters, as previously mentioned (Al-Ghamdi et al 2013;Chaouch et al 2013;Hilal et al 2012). The efficiency of the chemically activated date pits showed a three-fold increase compared with the raw date stones in terms of Cd 2+ adsorption capacity and the equilibrium time was achieved after 1 h (Hilal et al 2012).…”

“…The efficiency of the chemically activated date pits showed a three-fold increase compared with the raw date stones in terms of Cd 2+ adsorption capacity and the equilibrium time was achieved after 1 h (Hilal et al 2012). The values of other influential parameters for maximum adsorption were identified as particle size, 100 microns; temperature, 34°C; and mixing speed, 100-500 rpm (Al-Ghamdi et al 2013).…”

“…The adsorption of Cu 2+ was also studied extensively using DP based low-cost biosorbents (date stones, palm-tree waste, DP leaves pretreated with sulfuric acid and chemically activated date pits) (Belala et al 2011;Bouhamed et al 2012;Hilal et al 2012). A significant decrease in removal efficiency was observed with an increase in particle size and the adsorption process was deemed as endothermic, but was exothermic when using date stone and palm tree waste (Belala et al 2011).…”

“…Yadav et al (2013) reported that in case of Pb 2+ , the adsorption process was fast and equilibrium was established within 120 min. Hilal et al (2012) reported an equilibrium time of 60 min in the case of copper and cadmium adsorption using date pits with activation and non-activation. The fast adsorption process supports the application in wastewater treatment facilities as the operating time to separate metal ions is low and the cost of the process can be minimized.…”