Chemically modified palm kernel shell biochar for the removal of heavy metals from aqueous solution

Abstract

Heavy metals eradication from water is a complicated subject, therefore a viable, resilient, and green technology is imperative. Heavy metal removal can be accomplished through easy access, economical, and efficient sorbents derived from agricultural waste. In the current study, palm kernel shell (PKS) waste was converted into biochar (PKSC) via pyrolysis. Chemical modification was performed on PKSC via acid-base treatment to refine its adsorption properties. Batch experiments were conducted to study the efficiency of PKSC and acid-base treated PKSC (MPKSC) for removal of Cr(IV), Ni(II) and Cu(II). The surface area was increased from 112.934 m 2/g to 149.670 m 2/g by acid-based treatment. Batch adsorption study showed that the MPKSC afforded high removal efficiency for Cu (99.29%), Ni (96.77%) and Cr (42.97%). The Cr(IV) and Ni(II) adsorption by PKSC, as well as Cr(IV), Ni(II) and Cu(II) adsorption by MPKSC were best represented by Freundlich isotherm. However, Cu(II) adsorption by PKSC can explained by using Langmuir isotherm. All studied heavy metals fitted the pseudo-second-order kinetic.

The Role of Modified Biochar for the Remediation of Coal Mining-Impacted Contaminated Soil: A Review

“…Imran-Shaukat et al [122] reported the post-treatment of palm shell-derived biochar with 20% NaOH followed by acid treatment (HCl) to remove heavy metals from an aqueous solution. Samsuri et al [123] reported the application of Fe (III)-coated biochar for the removal of As (III) and As (V) from the aqueous solution, which was developed by impregnation of biochar particles with Fe ions in a solution containing FeCl 3 salt for 24 h. Lyu et al [124] reported the post-treatment of biochar with 0.063 moles of FeSO 4 aqueous solution to produce FeS-coated biochar particles to remove hexavalent chromium from the aqueous solution.…”

Removal of Ni(II) and Cu(II) in Aqueous Solutions Using Treated Water Hyacinth (Eichhornia crassipes) as Bioadsorbent

“…Studies conducted on various adsorbents treated with NaOH have indicated that the Langmuir, Freundlich, and Sips models offer better descriptions of the Ni(II) equilibrium adsorption process. In these studies, the adsorption capacities for Ni(II) were found to be 0.2, 0.123, and 41.75 mg/g using pineapple shell [64], peanut shell [44], and palm biochar [40], respectively. It was determined that the Langmuir model best fits the experimental data for the adsorption capacity of WL treated with HCl [32], methanol and acetonitrile [54], and citric acid [48].…”

“…In the case of WLN, the percentage of removal decreased from 58% to 37% for Ni and from 37% to 30% for Cu. This was due to the effect that occurred when the concentration of sites for the adsorption of metal ions remained constant, resulting in greater ease of disposition at these sites at low metal concentrations but preventing further metals from being removed from solution when the available sites became saturated [39][40][41][42][43][44][45].…”

“…In terms of Cu(II) adsorption in WLW, adsorption capacities of 293.82, 209.46, and 171.88 mg/g were obtained at 30, 45, and 60 • C, respectively, with a maximum removal percentage of 51.8%. The adsorption capacities of various adsorbents, including ZnCl 2activated carbon [64], almond shell [39], CoFeO 2 /SO 2 nanoparticles [55], bamboo modified with mercaptoacetic acid and carbon disulfide [61], magnetite-bentonite nanocomposites [15], lime shell [65], peanut shell [40], charcoal [60,61], hydroxyapatite [59], charred bones [62], sapropel humic acids [58], calcium alginate beads immobilized on rice bran [66], residual sludge [46], bentonite [43], and bentonite pretreated with CaCl 2 [52], ranged from 2.44 to 128.21 mg/g. These adsorbents used the Langmuir model to describe the adsorption of Cu(II) on their surfaces.…”

“…The maximum removal percentage obtained was 49.68%, which meant that despite losing efficiency in Cu(II) adsorption capacity, the removal percentage was not significantly affected by the treatment in WL. Palm biochar [40] and rice husk [68] exhibited adsorption capacities of 0.2 and 12.66 mg/g, respectively, when treated with NaOH. Furthermore, modifying the surface of orange peel with mercaptoacetic acid [69] resulted in an adsorption capacity of 70.67 mg/g.…”