Production of chitosan coated, citric acid modified almond, and hazelnut shell adsorbents for Cr(VI) removal and investigation of equilibrium, kinetics, and thermodynamics of adsorption

Altun, Türkan; Ecevit, Hüseyin; Çiftçi, Birsen

doi:10.1007/s12517-021-06631-4

Cited by 6 publications

(1 citation statement)

References 36 publications

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“…Another possible use of untreated HS based on its chemical composition, is as an adsorbent. Native (unmodified) hazelnut shells have been used for adsorptive removal of copper ions from water [22], dye removal [23] and chlorophenols [24], while modified hazelnut shells (in form of activated carbon or chemically modified) have been found to be effective for lead [25], cadmium, zinc, copper [26], uranium (VI) [27], arsenic (III) [28], chromium (VI) [29], methylene blue [30], crystal violet [31], and taxol (anticancer drug) [32] removal. After adsorptive removal of pollutants, the same material (now loaded with adsorbate) can be used directly as a fuel, eliminating the often difficult step of regeneration and disposal of the used adsorbent [23].…”

Section: Introductionmentioning

confidence: 99%

Modified Hazelnut Shells as a Novel Adsorbent for the Removal of Nitrate from Wastewater

Stjepanović

Velić

Habuda-Stanić

2022

Water

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The aim of the study was to prepare a novel adsorbent by chemical modification of hazelnut shells and evaluate its potential for the nitrate removal from model solutions and real wastewater. The characterization of the novel adsorbent, i.e., modified hazelnut shell (MHS) was performed. The adsorbent characterization included the analysis of elemental composition and the surface characteristics analysis by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The adsorption experiments (batch technique) were performed to investigate the effects of adsorbent concentration, contact time, initial nitrate concentration, and solution pH. The nitrate removal efficiency increased with the increase in MHS concentration and decreased with the initial nitrate concentration. MHS was found to be effective in nitrate removal over a wide pH range (from 2 to 10), and the highest amount of nitrate adsorbed was 25.79 mg g−1 in a model nitrate solution. Depending on the aqueous medium (model solutions or real wastewater samples), it was shown that both Langmuir and Freundlich adsorption isotherm models can be used to interpret the adsorption process. It was found that the kinetics are well described by a pseudo-second order model and the nitrate adsorption process can be controlled by chemisorption. The intraparticle diffusion model has been used to identify an adsorption-controlled process by diffusion mechanisms. Adsorption/desorption experiments in column confirmed that MHS could be successfully used in multiple cycles (at least three), indicating the potential of MHS as an alternative to costly commercial adsorbents for the removal of nitrates from wastewater.

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