Effective Removal of Hexavalent Chromium from Polluted Water using Phoenix sylvestris Seed Powder as Adsorbent

Meghana, P. Karunasri; Pravalika, K. Venkata; Sriram, P. Janaki; Ravindhranath, K.

doi:10.14233/ajchem.2019.21760

Cited by 2 publications

(1 citation statement)

References 41 publications

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“…Similar results were obtained under the same operating conditions using a biosorbent derived from the plant Cassia occidentalis, indicating that it can also be a viable biomaterial for the removal of aluminum present in real effluents [125].…”

Section: Practical Applicationssupporting

confidence: 73%

Aplicação do resíduo da extração sólido-líquido de alginato da alga Sargassum filipendula para bioadsorção de íons alumínio

Pereira de Sá Costa

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Aluminum is a metal classified as toxic and its extensive use in industrial processes generates large amounts of effluents contaminated. Such effluents are usually disposed of in water bodies, but the legislation requires pre-treatment of these before their disposal. Therefore, this work aims to analyze the efficacy of the residue from the solid-liquid extraction of alginate (here called RES) in the removal of aluminum ions. The experimental design of the Rotational Central Composite Design (RCCD) associated with the Response Surface Methodology (RSM) was carried out to determine optimal values of important factors in the operation and showed that the agitation has no significant impact on the process, since the concentration of the solution and the dosage of the biomass is directly proportional to each other, so the optimized RES dosage was set at 2 g/L, while the aluminum initial concentration up to 3 mmol/L reveals to favor the process. pH showed to be a very influent parameter in the aluminum biosorption by RES and, better removal results were obtained at pH 4. The kinetic study revealed that the process equilibrium time (60 min) was not influenced by the increase in the initial concentration. Mathematical modeling indicated the occurrence of more than one removal mechanism, being associated with physical and chemical interactions such as ion exchange. In addition, the equilibrium model adjustments revealed that the residue has an energetically heterogeneous surface. The maximum removal capacity obtained was 1.431 mmol/g at 25 ºC. Thermodynamic study revealed that the process is exothermic and spontaneous. The simplified batch design showed that a small amount of waste (140 g) is needed to treat 10L of solution, removing 90% of aluminum at 1 mmol/L. The biosorbent was characterized before and after Al adsorption and the analyses indicated that the biomaterial is basically composed of macropores, in addition to having considerable thermal resistance at temperatures up to 150 ºC. In the efficiency comparison, the biomaterial stands out in relation to other biosorbents derived from algae previously studied for the removal of aluminum. The evaluation of ion exchange along with SEM-EDX analysis showed that sodium ions are the main exchangeable cations involved in the bio-absorption mechanism of the Al-RES system, followed by calcium, magnesium and a small share of potassium ions. The FTIR analysis and the functional group esterification test showed that mainly carboxylic groups, amine and sulfonate are involved in the studied biosorption system. The fixed bed study showed that the optimized parameters of continuous operation were a feed flow rate of 0.5 mL/min and an initial aluminum concentration of 1 mmol/L. Under these conditions the breakthrough time was about 200 minutes with a satisfactory percentage of aluminum removal (93%). The eluent tested most suitable for the regeneration of the biosorbent was the acid solution of 0.1 mol/L of HNO3. The residue demonstrated viable application, maintaining good perform...

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Section: Practical Applicationssupporting

confidence: 73%

Aplicação do resíduo da extração sólido-líquido de alginato da alga Sargassum filipendula para bioadsorção de íons alumínio

Pereira de Sá Costa

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Calcium Alginate Beads Doped with Nano-ZrO2 and Activated Carbon of Annona reticulate Plant as an Effective Adsorbent for Water Remediation of Chromium(VI)

Biftu

Ravindhranath

2021

Asian J. Chem.

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An activated carbon produced from stems of Annona reticulate plant (SACAR) by conc. H2SO4 digestion, is observed to have strong affinity for toxic Cr(VI) ions. Its adsorptivity for Cr(VI) ions was enhanced by admixing it with ‘nano-ZrO2’ (Zr-SACAR)-synthesized adopting green methods. For ensuring easy filtration, the ‘active carbon + nanoparticle composite’ was immobilized in calcium alginate beads (Zr-SACAR-Ca). Optimum extraction conditions for these three adsorbents for the removal of Cr(VI) ions from water were investigated. The adsorption capacities were found to be 92.2 mg/g for SACAR; 109.83 mg/g for Zr-SACAR and 119.34 mg/g for Zr-SACAR-Ca. The sorption nature was characterized by XRD, FTIR, FESEM and EDX studies. The sorption mechanism was investigated using various isotherm models. Thermodynamic studies revealed the endothermic and spontaneous nature of sorption. The kinetics of adsorption was well defined by the pseudo-second-order model. The spent adsorbent are regenerated and reused until six cycles with marginal decrease in Cr-adsorptivity. The adsorbents developed are effectively applied in the treatment of polluted water samples collected from Ethiopia

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Effective Removal of Hexavalent Chromium from Polluted Water using Phoenix sylvestris Seed Powder as Adsorbent

Cited by 2 publications

References 41 publications

Aplicação do resíduo da extração sólido-líquido de alginato da alga Sargassum filipendula para bioadsorção de íons alumínio

Aplicação do resíduo da extração sólido-líquido de alginato da alga Sargassum filipendula para bioadsorção de íons alumínio

Calcium Alginate Beads Doped with Nano-ZrO2 and Activated Carbon of Annona reticulate Plant as an Effective Adsorbent for Water Remediation of Chromium(VI)

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