Abstract
Activated carbons were obtained from the peelings of cassava tubers (Manihot esculenta) by chemical activation using potassium hydroxide and phosphoric acid at impregnation ratios of 2 : 1 and 1 : 1, respectively, at 400°C for batch adsorption of nickel(II) ions from aqueous solution. Characterization of activated carbon samples was achieved via proximate analysis, Fourier-transform infrared spectroscopy, pH of zero-point charge, Boehm method, elemental analysis, scanning electron microscopy, and iodine number determination for each adsorbent. The effects of pH, contact time, initial adsorbate concentration, and adsorbent dose were studied at 27°C in order to optimize the conditions for maximum adsorption. Equilibrium was attained after 40 minutes of contact of both materials with activating solutions. Maximum adsorption capacities of 41.15 mg/g for ACPH, 47.39 mg/g for ACPA, 35.34 mg/g for NIC, and 34.48 mg/g for RM, respectively, were obtained at pH = 4. Equilibrium data showed that the Langmuir model best described the adsorption process with R2 closed to unity, indicative of monolayer adsorption on a homogeneous surface. Kinetic studies showed that the adsorption process is controlled by the pseudo-second-order model. These results show that activated carbon prepared from cassava peelings constitutes an effective low-cost material for the treatment of wastewater containing nickel(II) ions.
Highlights
Pollution by heavy metals is a global health and environmental concern [1]
During the chemical activation process, reagents such as inorganic salts (ZnCl2, FeCl3, KHCO3, NaCl, MgCl2, Na2CO3 CaCl2, and K2CO3), acids (HNO3, H2SO4, and H3PO4), or soluble bases (NaOH, KOH) are often used [14]. ese chemical agents favor the dehydration of materials and allow for the development of micropores [15]. e objective of this study was to evaluate the performance of activated carbons obtained by chemical activation with KOH and H3PO4 of the peelings of cassava tubers (Manihot esculenta) for the removal of nickel(II) from aqueous solution
Cassava tuber peelings were acquired in great quantity from a local factory in Santchou village situated in the West Region of Cameroon which is involved in the processing of cassava-based foodstuff. ey were transported to the laboratory after undergoing thorough washing and cleaning under tap and distilled water for the removal of residual soil and other impurities
Summary
Pollution by heavy metals is a global health and environmental concern [1]. Nickel is a nonbiodegradable and toxic heavy metal, which is ubiquitous in wastewater bodies in various proportions [2]. e main origin of nickel pollution in water is from industrial processes such as galvanization, smelting mining, dyeing operation, battery manufacturing, and metal finishing [3]. Nickel is a nonbiodegradable and toxic heavy metal, which is ubiquitous in wastewater bodies in various proportions [2]. Conventional methods for nickel(II) removal from wastewater include chemical oxidation or reduction, chemical precipitation, ion exchange, membrane separation, filtration, electrochemical treatment, and adsorption [5]. Adsorption techniques using organic, inorganic, natural, synthetic, activated, or modified adsorbents are the most widely employed procedures in wastewater treatment and constitute low-cost alternatives. Potential low-cost adsorbents (activated or not) for heavy metal removal include the following: Journal of Chemistry. E objective of this study was to evaluate the performance of activated carbons obtained by chemical activation with KOH and H3PO4 of the peelings of cassava tubers (Manihot esculenta) for the removal of nickel(II) from aqueous solution During the chemical activation process, reagents such as inorganic salts (ZnCl2, FeCl3, KHCO3, NaCl, MgCl2, Na2CO3 CaCl2, and K2CO3), acids (HNO3, H2SO4, and H3PO4), or soluble bases (NaOH, KOH) are often used [14]. ese chemical agents favor the dehydration of materials and allow for the development of micropores [15]. e objective of this study was to evaluate the performance of activated carbons obtained by chemical activation with KOH and H3PO4 of the peelings of cassava tubers (Manihot esculenta) for the removal of nickel(II) from aqueous solution
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