Chemically Activated Carbon Based on Biomass for Adsorption of Fe(III) and Mn(II) Ions from Aqueous Solution

Abstract

Rice husk was converted into activated carbon (AC) as a byproduct of agricultural waste in an electric furnace at 700 °C and chemically activated using three distinct processes: NaOH AC(C), acetic acid AC(C-1), phosphoric acid AC(C-2), and carbonization AC(C-3) without any chemical activation. To characterize the activated carbon and the removal efficiencies of Fe(III) and Mn(II) from aqueous solutions, various analytical tools were used. The results revealed that the capacities of the four adsorbents to adsorb Fe(III) or Mn(II) from an aqueous solution differ significantly. AC(C-3) was chosen for additional research. The impact of different operational factors, including pH, contact time, adsorbent dosage, starting metal ion concentration, interfering ions, and temperature, were investigated. The optimum pH values for Fe(III) and Mn(II) adsorption were found to be pH 3 and pH 6, respectively. The results obtained were utilized to assess the kinetics and thermodynamics of the adsorption process. The sorption of Fe(III) and Mn(II) ions was found to be a pseudo-second-order kinetic process, and the equilibrium data were fitted with the Langmuir isotherm. Additionally, the evidence suggests that an endothermic mechanism governs the adsorption process. The maximum adsorption capacities of Fe(III) and Mn(II) were 28.9 and 73.47 mg/g, respectively.

Applicability of Natural Coffee Husk as a Mesoporous Adsorbent for Removal of Chromium (VI) from Aquatic Environments

“…Figure 4 (f) and Table 3 present the determination result. The values of K T = 1.25 L g -1 , R 2 = 0.98, and B=-8.81 kJ mol -1 establish the physisorption nature of the adsorption of Cr (VI) onto coffee husk from aqueous solution (Elewa et al, 2023). In a similar finding, equilibrium data using activated charcoal for Cr (VI) removal fit the Langmuir model with an adsorption capability of 45.24 g kg -1 at pH 2 (Alfa-Sika et al, 2010).…”

“…In Figure 4 (e) and Table 3, R 2 0.92 indicates that the adsorption processes did not obey the Freundlich isotherm and 1/n= -0.79, which is less than 1, so the sorption is unfavorable (Elewa et al, 2023). The Temkin model postulates that the heat of analyte adsorption in the surface layer decreases linearly with increased surface coverage because of the interaction between the absorbent and adsorbate.…”

“…Many techniques are used for expulsion of wastewater, including natural strategies, biochemical strategies, synthetic oxidation, and photograph catalysis (Argun et al, 2007). In the last two decades, a few advancements have been made in the treatment of metals containing watery arrangement (Hamad et al, 2015;Elewa et al, 2023). Conventional methods for removing Cr (VI) ions from industrial wastewater include reduction and chemical precipitation (Kim et al, 2002), adsorption of activated carbon, solvent extraction (Samson & Adedibu 2016), electrochemical sensors, reverse osmosis, and ion exchange (Ruiyu et al, 2021).…”

“…The significant advantages of biosorption over traditional treatment strategies include the following: it is easy to obtain; it is highly effective; it involves minimization of the pollutant as well as organic slime; biosorbents are recovered; no extra supplements are necessary; and there is a probability of metal recuperation. Moreover, adsorbent materials from agriculture wastes can be used for maximum adsorption and recovery of heavy metal ions from wastewater streams (Yang et al, 2014;Alhogbi, 2017;Elewa et al, 2023). The processing of coffee generates large amounts of solid residues.…”

“…The real principal points of biosorption innovation are its viability in decreasing the convergence of heavy metal particles to low levels and its use of cheap biosorbent materials. The cost efficiency of biosorption innovation would ensure solid infiltration of the massive market for substantial metal-contaminating enterprises (Kumar et al, 2017;Ghorbani, et al, 2020;Elewa et al, 2023). Therefore, this study aims to determine the applicability of the adsorption properties of natural coffee husk for the removal of Cr (VI) ions from aquatic systems by studying factors affecting the removal process (e.g., pH, mass dosage, KNO 3 concentration, contact time, and different temperature) as well as examining characterization by the Brunauer Emmett Teller (BET) and Fourier Transform Infrared (FTIR) techniques.…”