Kinetics of Mercury and Nickel Adsorption Using Chemically Pretreated Cocoa (Theobroma cacao) Husks

Abstract

Abstract. Agroindustrial wastes have been widely used to prepare adsorbents for heavy metal removal because of their low cost, accessibility, and high efficiency. This work focuses on preparing a novel material from cocoa ( L.) husk residual biomass chemically modified with sodium hydroxide for used as a biosorbent for nickel and mercury uptake. The cocoa husk residual biomass was characterized by FT-IR analysis to test the diversification of functional groups. The effect of particle size on removal yield was evaluated through batch adsorption experiments. The experimental results were fitted to mathematical models to determine the adsorption kinetics and isotherms. Particle size significantly affected the adsorption process, and the highest removal yields (91.59% and 79.96%) were achieved using 0.36 mm and 0.5 mm particles for Hg (II) and Ni (II) ions, respectively. The adsorption kinetic model that best fit the experimental data corresponded to the Elovich model, with correlation coefficients (R2) above 0.89. The adsorption process of nickel and mercury onto cocoa husk biomass followed the Freundlich isotherm model. The results show that modification with sodium hydroxide improves the adsorption capacity of cocoa husk residual biomass, indicating that this novel material could be efficiently applied for nickel and mercury uptake. Keywords: Adsorption, Heavy metals, Removal yield.

Adsorption Processing for the Removal of Toxic Hg(II) from Liquid Effluents: Advances in the 2019 Year

“…Elution data were not included in the publication. An adsorbent derived from cocoa (Theobroma cacao L.) husk residual biomass chemically modified with sodium hydroxide was to Hg(II) (and Ni(II)) [100]. Particle size significantly affected the adsorption process.…”

Adsorción de cromo (VI) y mercurio (II) en solución utilizando jacinto (Eichhornia crassipes)

“…We worked with 100 mL of the solution with a concentration of 100 ppm and 0,5 g of biomass of each particle size of the biomass already crushed (0,355 mm, 0,5 mm and 1 mm) placing them in a Beaker with stirring for 2 hours at 150 rpm, extracting samples of 3 mL at the end of the agitation. The analysis of the final concentration of the metal in the liquid phase is carried out by the method of diphenylcarbazide and ammonium diocyanate at 584 and 281 nm, for Cr (VI) and Hg (II) respectively, in a UV-vis spectrophotometer [5,18]. The experiments were carried out in duplicate.…”

“…To determine the equilibrium time of adsorption, the kinetics were carried out taking aliquot of 3 mL every 30 minutes, performing independent experiments, so as not to affect the concentration of the metals in the solution. The adsorption isotherms were applied to analyze the metal adsorption equilibrium data in the evaluated adsorbent, for the realization of the assays initial concentrations of 25, 50, 75 and 100 ppm were used [5,22]. All the tests were carried out in triplicate, taking the arithmetic average of the data, the consistency of the data was verified by calculating the standard deviation and the analysis of the data was made using OriginPro 8 ®.…”

“…On the other hand, the presence of heavy metals in bodies of water implies risks for human public health, given their non-biodegradation and high toxicity [4,5]. The most common metals present in water are: Cadmium, Cobalt, Copper, Manganese, Hg (II), Nickel, Lead and Zinc; which are produced in activities such as agriculture, metallurgy, energy production, microelectronics, mining, sewage sludge and waste disposal [6,7].…”

Determination of Kinetic Parameters in the Biosorption of Chromium (VI) in Aqueous Solution

“…The use of biomass from agricultural residues as adsorbents has been widely researched, due to the low cost, immediate availability and high removal efficiency. Various bio-adsorbents such as plantain peels [6], [13], cassava shells [14], orange peels [15], rice husk [5], cocoa peels [16], tea waste [17], potato husks [1], lemon [18], coffee pulp [19], and other husks were tested for the removal of these contaminants [20], [21]. Therefore, in the present study, the adsorption kinetics of Cr (VI) in aqueous media were investigated using plantain peels, at different temperature conditions ( • C), adsorbent dose (g) and particle size.…”