Lignocellulosic Based Biochar Adsorbents for the Removal of Fluoride and Arsenic from Aqueous Solution: Isotherm and Kinetic Modeling

Abstract

Eucalyptus wood is made up of lignocellulosic material; this lignocellulosic material contains two types of biopolymers, i.e., carbohydrate and aromatic polymers. In this study, this lignocellulosic material was used to prepare biochar. Three biochar, i.e., laboratory-based (B1), barrel-based (B2), and brick kiln-biochar (B3), were used for fluoride and arsenic removal from aqueous solution. Barrel-based biochar was prepared by using the two-barrel method’s alteration. The highest fluoride removal (99%) was attained at pH 2 in the presence of B1, while in the presence of B2 and B3, maximum fluoride removal was 90% and 45.7%, respectively. At pH 10, the maximum arsenic removal in the presence of B1, B2, and B3 was 96%, 94%, and 93%, respectively. The surface characteristics obtained by Fourier-transform infrared spectroscopy (FTIR) showed the presence of carbonyl group (C-O), and alkene (C=C) functional groups on all the three studied biochars. Isotherm studies showed that the adsorption was monolayered (all the adsorbed molecules were in contact with the surface layer of the adsorbent) as the Langmuir isotherm model best fits the obtained data. Adsorption kinetics was also performed. The R2 value supports the pseudo-second-order kinetics, which means that chemisorption was involved in adsorbing fluoride and arsenic. It is concluded that B1 gives maximum removal for both fluoride (99%) and arsenic (96%). The study shows that lignocellulose-based biochar can be used for arsenic and fluoride removal from water.

Metal‐Loaded Biochar for the Removal of Arsenic from Water: A Critical Review on Overall Effectiveness, Governing Mechanisms, and Influential Factors

“…Vishnoi et al [71] ChemistrySelect Ayaz et al [112] Ginkgo leaves biochar Wen et al [113] ChemistrySelect carbon dilatation, amplification of the amorphous form, and lattice defects in the C structure, which are responsible for micropore creation. [94] The specific surface area and total pore volume of H 3 PO 4 treated modified biochar were enlarged over ten times.…”

Performance of Rod-Shaped Ce Metal–Organic Frameworks for Defluoridation

“…Specifically, an appropriate adsorbent should possess high adsorption efficiency, a fast adsorption rate, excellent water stability and mechanical strength, high selectivity for fluoride, and easy production; furthermore, it should fulfil economic and environmental requirements. Several types of adsorbents have been exploited for F − elimination, such as zeolite, hydroxyapatite, biochar, bentonite, metal-organic frameworks (MOFs), and layered double hydroxides [13][14][15][16][17][18]. However, most of these adsorbents suffer from low adsorption capacity, poor selectivity, and high treatment costs; thus, the development of superior adsorbents still constitutes an important yet challenging task.…”