Adsorption and desorption studies of <i>Delonix regia</i> pods and leaves: removal and recovery of Ni(II) and Cu(II) ions from aqueous solution

Abstract

Abstract. In this study, the adsorption of Ni(II) and Cu(II) ions from aqueous solutions by powdered Delonix regia pods and leaves was investigated using batch adsorption techniques. The effects of operating conditions such as pH, contact time, adsorbent dosage, metal ion concentration and the presence of sodium ions interfering with the sorption process were investigated. The results obtained showed that equilibrium sorption was attained within 30 min of interaction, and an increase in the initial concentration of the adsorbate, pH and adsorbent dosage led to an increase in the amount of Ni(II) and Cu(II) ions adsorbed. The adsorption process followed the pseudo-second-order kinetic model for all metal ions' sorption. The equilibrium data fitted well with both the Langmuir and Freundlich isotherms; the monolayer adsorption capacity (Q0 mg g−1) of the Delonix regia pods and leaves was 5.88 and 5.77 mg g−1 for Ni(II) ions respectively and 9.12 and 9.01 mg g−1 for Cu(II) ions respectively. The efficiency of the powdered pods and leaves of Delonix regia with respect to the removal of Ni(II) and Cu(II) ions was greater than 80 %, except for the sorption of Ni(II) ions onto the leaves. The desorption study revealed that the percentage of metal ions recovered from the pods was higher than that recovered from the leaves at various nitric acid concentrations. This study proves that Delonix regia biomass, an agricultural waste product (“agro-waste”), could be used to remove Ni(II) and Cu(II) ions from aqueous solution.

Blighia sapida Waste Biochar in Batch and Fixed-Bed Adsorption of Chloroquine Phosphate: Efficacy Validation Using Artificial Neural Networks

“…The percentage removal increased marginally from 91.81 to 99.30% as the BSSP dosage increased to 0.10 from 0.05 g/100 mL (Figure ). This may be attributed to the rise in the number of active sites that are currently available as the BSSP dosage increased, which in turn increased the surface area, resulting in a higher percentage removal . Also, the percentage removal decreased slightly as the dosage was further increased from 0.10 to 0.25 g (99.30–92.61%).…”

“…This may be attributed to the rise in the number of active sites that are currently available as the BSSP dosage increased, which in turn increased the surface area, resulting in a higher percentage removal. 44 Also, the percentage removal decreased slightly as the dosage was further increased from 0.10 to 0.25 g (99.30− 92.61%). This could be due to active site overlapping caused by excess BSSP particles.…”

Investigation of Adsorptive Removal of Methylene Blue from Synthetic Wastewater Using Polymeric Composite

“…The R 2 value is highly significant. Based on 𝑅 2 values of these isotherm models, it was concluded that the Freundlich, Jovanovich, Dubinin-Radushkevich, Temkin isotherms, and Langmuir 1,2 were better models than the Harkin-Jura model, however, Harkin-Jura constant, A values greater than 1, suggest better curve fitting, and the adsorption is favorable for Harkin-Jura isotherm (12,21).…”

Effect of Chemical Modifications on the Adsorptive Ability of Palm Kernel Fiber for Indigo Blue Dye

“…It thus, becomes an issue of paramount importance to treat dye containing wastewater and effluents from industrial processes where dyes are used before they are discharged. Conventionally, treatments such as chemical precipitation, flocculation, electro-floatation, microbial biodegradation, ion-exchange, ozonation and membrane filtration, adsorption and advanced treatment techniques [3][4], have been used to treat and remove dyes from wastewaters but not without limitations or disadvantages in terms of energy requirement such as reagent needed and power supply, sludges that require further treatment before it is suitable for discharge [2,5]. Adsorption, seems to be the most promising among these methods since its design is simple to adapt and modify, has been efficiently applied to many wastewaters systems without the generation of toxic sludge [6], there's easy recovery of adsorbate, possibility of tuning adsorbent properties, high regeneration capacity and involves low cost in comparison with other used techniques [7].…”