Valorization of agricultural waste into activated carbons and its adsorption characteristics for heavy metals

Abstract

Activated carbon derived from pine cones waste was prepared by carbonization at 450 • C, activated by different activating agents: ZnCl 2 , H 2 SO 4 and NaOH, and then pyrolyzed at 600 • C. Adsorption of Cr VI and other heavy metals (Mn II, Fe II, Cu II) on activated carbons was investigated to evaluate the adsorption properties. Special attention was paid to the effects of carbon surface functionalities that were analyzed by FT-IR and zeta potential study. Moreover, XRD study of activated carbon was also carried out. Results had shown that activated carbon by NaOH was the best adsorbent for removal of chromium VI from wastewater. The solid-solution interaction was determined by analyzing the adsorption isotherms at room temperature at different pH. When pH is above 4, the removal fraction of Cr (VI) ions decreased with the increase of pH. The removal fraction of Cr (VI) ions decreased below pH 4. The preferable removal of Cu (II) over Mn(II) and Fe (II) could be due to its lower affinity to solvent.Pseudo-second order equation provided the better correlation for the adsorption kinetics data. Equilibrium isotherms were determined by Fowler-Guggenheim model.

One-, Two-, and Three-Parameter Isotherms, Kinetics, and Thermodynamic Evaluation of Co(II) Removal from Aqueous Solution Using Dead Neem Leaves

“…e entire W values are negative, becoming more negative with increasing loading or increasing initial concentration indicating that the heat of adsorption shows a decrease with loading due to repulsive interaction among adsorbed molecules. Other authors [56] also reported that the Fowler-Guggenheim model best described Cr (VI), Mn(II), Fe(II), and Cu(II) on activated carbons from agricultural wastes but with positive W values.…”

Potential Use of Hazelnut Processing Plant Wastes as a Sorbent for the Simultaneous Removal of Multi-Elements From Water

“…It is important to note that arsenic (As) is a metalloid and selenium (Se) is a nonmetal, however, the term "heavy metal" will be used for the description of the elements studied in this paper. Although trace concentration of some of these elements (Fe, Cu, Cr, Zn, Se, Mn, Ni) are vital for some biochemical processes and physiological functions, they can persist in the environment and can cause serious health problems even at low concentrations (Ali et al, 2016;Amuda et al, 2007;Aremu et al, 2002;Chowdhury et al, 2016;Gautam et al, 2014;Karadag, 2008;Koubaissy et al, 2014;Li et al, 2017;Sencan et al, 2015;Wan Ngah and Hanafiah, 2008;Wang and Chen, 2006).…”

“…Several processes such as coagulation/flocculation, oxidation/precipitation, adsorption/biosorption, electrochemical processes, ion-exchange, bioremediation, floatation, evaporation, photocatalysis and membrane technology can be used for the removal of heavy metals (Barakat, 2011;Bestawy et al, 2012;Blöcher et al, 2003;Gunatilake, 2015;Wahyuni et al, 2015). Among these methods, adsorption/biosorption is one of the preferred methods due to its easy application, cost effectiveness, high efficiency, regeneration capacity, easy recovery and sludge-free operation (Amuda et al, 2007;Aremu et al, 2002;Gautam et al, 2014;Kadirvelu et al, 2001;Karadag, 2008;Koubaissy et al, 2014;Vaghetti et al, 2009;Zhang et al, 2016).…”

“…However, because of its high cost, researchers tended to find alternative, cheaper and naturally occurring adsorbents in recent years. Agricultural wastes such as peanut, hazelnut, walnut, rice husk, cotton stalk, etc., which have lignocellulosic structures can be considered as most appropriate adsorbents for the removal of pollutants (Ali et al, 2016;Koubaissy et al, 2014;Wan Ngah and Hanafiah, 2008;Wolfová et al, 2013).…”

Adsorption of uremic toxins over dealuminated zeolites

“…Wernert et al (2005) mentioned the use of activated carbon as adsorbent for different uremic toxins. Activated carbon is characterized by its highly developed porosity, large surface area, variable characteristics of surface chemistry, and high degree of surface reactivity (Koubaissy et al, 2014).…”