Hexavalent chromium removal by polyacrylic acid-grafted <i>Macadamia</i> nutshell powder through adsorption–reduction mechanism: Adsorption isotherms, kinetics and thermodynamics

Ntuli, Themba D.; Pakade, Vusumzi Emmanuel

doi:10.1080/00986445.2019.1581619

Cited by 28 publications

(12 citation statements)

References 64 publications

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“…Besides electrostatic attraction, the removal of Cr(VI) by MACA/B/F at low pH could also be due to the reduction of Cr(VI) to the less toxic Cr(III). The reduction is promoted by the acidic conditions and the presence of electron‐donating groups like NH, SH, and OH on the surface of adsorbents (Ntuli & Pakade, 2020). The CHNS analysis illustrated a lack of S and N atoms in the biosorbents, and therefore, O atoms were assumed to be responsible for the transformation of Cr(VI) to Cr(III).…”

Section: Resultsmentioning

confidence: 99%

“…The CHNS analysis illustrated a lack of S and N atoms in the biosorbents, and therefore, O atoms were assumed to be responsible for the transformation of Cr(VI) to Cr(III). The diminished percentage removal of Cr(VI) at higher pH was attributable to the presence of hydroxide ion (OH‐), which then competes for adsorption sites with Cr(VI) anions (Fathy et al, 2015; Ntuli & Pakade, 2020).…”

Section: Resultsmentioning

confidence: 99%

“…All chemicals were used without further purification. The Cr(VI) stock solution, working solutions, and its analysis on T80+ UV–Vis spectrometer were conducted as reported in Ntuli and Pakade (2020). The purified water used in the study was obtained from Siemens LaboStar equipment (Johannesburg, South Africa).…”

Section: Methodsmentioning

confidence: 99%

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A comparative study of acid‐treated, base‐treated, and Fenton‐like reagent‐treated biomass for Cr(VI) sequestration from aqueous solutions

Nchoe

Ntuli

Klink

et al. 2020

Water Environment Research

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A wide variety of biomass materials have been used for the removal of toxic chromium(VI) by biosorption. The current study investigated the efficacy of Macadamia nutshells treated with sodium hydroxide, nitric acid, and the Fenton‐like reagent in the removal of Cr(VI). The adsorbents were characterized by FTIR, SEM, TGA, and elemental analysis. Effects of functional parameters influencing the adsorption of Cr(VI), solution pH (pH 1–11), contact time (5–250 min), concentration of adsorbent (1–10 g/L), and adsorbate concentration (10–200 mg/L) were investigated. The optimum conditions for biosorption were pH 1.4, adsorbent dose of 5 g/L, and 160 min of contact time. In all cases, the base‐treated adsorbent displayed superior performance compared to others, with highest percent removal of 98%. The adsorbate–adsorbent interactions were better explained by the Freundlich isotherm and the pseudo‐first‐order rate model. The Macadamia‐based adsorbents are potentially useful for Cr(VI) removal from aqueous solutions. Practitioner points Three different chemical activators were investigated for the modification of Macadamia surface. The base‐treated material exhibited the highest specific surface area of 12.1 m2/g. The Cr(VI) adsorption performance for the base‐treated material dwarfed the other materials. Excellent Cr(VI) removal efficiency in the presence of competitors was achieved.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

A comparative study of acid‐treated, base‐treated, and Fenton‐like reagent‐treated biomass for Cr(VI) sequestration from aqueous solutions

Nchoe

Ntuli

Klink

et al. 2020

Water Environment Research

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“…The synergy in adsorption and reduction during the removal of Cr(VI) by adsorbents has been mentioned by several researchers. 16,29,30,44,162,163 Anionic Cr(VI) could be adsorbed through electrostatic bonding on protonated sites or through anion exchange. The strong oxidant nature of Cr(VI) causes the surface where it was bonded to be oxidized while itself is reduced to Cr(III).…”

Section: àmentioning

confidence: 99%

Recent advances in hexavalent chromium removal from aqueous solutions by adsorptive methods

2019

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“…This has therefore lead to the search for the low cost and effective method for the removal of the heavy metal ions from aqueous solution. Studies have shown that various adsorbents have been used to remove metal ions from water, such includes; nanochitosan and chitosan [23], multiwalled carbon nanotubes modified by diphenylcarbazide [24], lemon peel [25], esterified spent grain [26], polyacrylic acid-grafted Macadamia nutshell powder [27], olive stone [28], banana pith [29] among others.…”

Section: Introductionmentioning

confidence: 99%

Equilibrium Studies for Removal of Cadmium (II) Ions Removal from Water Using Activated Carbon Derived from Macadamia Intergrifolia Nutshell Waste Powder

Kamau

Thiong’o

Kakoi

2020

IRJPAC

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Heavy metals have continued to be of great concern in research as major pollutants of water. Adsorption using low cost adsorbent is a low cost method of the removal heavy metal ions from aqueous solution. In this study activated carbon derived from macadamia intergrifolia nutshell powder was considered as an alternative low cost adsorbent for the removal of Cd(II) ions from aqueous solution. Various physicochemical parameters which included sorbent mass, and initial metal ions concentration isotherms using sorption models were determined. Results from the experiment indicated the optimum values for sorbent mass as 0.3 grams, and initial metal ions concentration as 8mg/l. Adsorption isotherms were found to fit well in Langmuir model (R2=0.9935), Javanovic model (R2 =0.9857) and Freundlich model (R2=0.9911). Additionally, for Langmuir model the value of separation factor (KL) was in the range of 0 to 1 indicating a favorable reaction. For Jovanovic model adsorption energy was found to be 1.00334 l/mg thus an indication of binding vibrations during Cd(II) ions adsorption. FTIR spectrum revealed that the presence of O-H at νmax 3389 cm-1, COO- at νmax 2367 cm-1, C=0 at νmax 1593 cm-1, C-O at νmax 1344 cm-1, P-O at νmax 1206 cm-1 and POO-H at νmax 1110cm-1 functional group in activated carbon enhanced Cd(II) ions removal. The study revealed that activated carbon derived from macadamia intergrifolia nutshell can be used to remove Cd(II) ions from water.

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Hexavalent chromium removal by polyacrylic acid-grafted Macadamia nutshell powder through adsorption–reduction mechanism: Adsorption isotherms, kinetics and thermodynamics

Cited by 28 publications

References 64 publications

A comparative study of acid‐treated, base‐treated, and Fenton‐like reagent‐treated biomass for Cr(VI) sequestration from aqueous solutions

A comparative study of acid‐treated, base‐treated, and Fenton‐like reagent‐treated biomass for Cr(VI) sequestration from aqueous solutions

Recent advances in hexavalent chromium removal from aqueous solutions by adsorptive methods

Equilibrium Studies for Removal of Cadmium (II) Ions Removal from Water Using Activated Carbon Derived from Macadamia Intergrifolia Nutshell Waste Powder

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