| Abstrakt: |
The study was designed to synthesize microporous activated carbons from the wastes of three medicinal herbs by NaOH as an activator followed by pyrolysis. The prepared microporous activated carbons R. Weed (Amaranthus retroflexus Redroot pigweed modified with NaOH), S. Bod Magnolia soulangeana Soul-Bod treated with NaOH) and S. TY (Tanacetum Vulgar L. (Tansy) treated with NaOH) were deployed for dangerous Cr(VI) ion remediation from the aquatic system. The synthesized modified biosorbents were described by FT-IR, SEM, EDAX, and BET. Furthermore, it was found that biosorbent made from R. Weed seems to have a surface area of 588.155 m2/g and micropore volume of 0.331Cm3/g whereas biosorbent made from S. Bod and S. TY does have a surface area of 489.613 and 445.615 m2/g respectively. The effects of several variables such as pH, temperature, and contact time were explored. The kinetic studies were accomplished and it was noticed that equilibrium was confirmed at 6 min for R. Weed while at 8 and 10 min for S. Bod and S. TY respectively. The pertinence of different adsorption isotherms like Langmuir, Freundlich, and Temkin was explored. The optimum adsorption capacity for each adsorbent material in respect of monolayer coverage (Qmax) was calculated. The Qmax of Redroot pigweed (R. Weed), Soul-Bod (S. Bod), and Tansy (S. TY) biosorbents were 326.62, 181.69, and 108.14 mg/g respectively. The adsorption kinetics was described using pseudo-first-order and pseudo-second-order equations. Furthermore, it was found that each adsorbent material followed the pseudo-second-order kinetics which affirmed the chemosorption nature of adsorption. The thermodynamic variables that include ΔG, ΔH, and ΔS were determined for each adsorbent material. Moreover, the manufactured R. Weed biosorbent seems to have high recyclability. It will remediate Cr(VI) ions with a maximum remediation efficiency of up to 81% during six cycles of regeneration. [ABSTRACT FROM AUTHOR] |
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