Metal ion free watermelon (Citrullus lanatus) rind as adsorbent for the removal of lead and copper ions from aqueous solution

Abstract

A B S T R A C TChemically protonated watermelon rind (PWR) was evaluated as a low-cost and efficient adsorbent for the removal of Pb 2+ and Cu 2+ ions from aqueous solution. Protonation of watermelon rind (WR) was carried out with 0.1 M HCl as protonating agent. The adsorption process was found to be spontaneous and exothermic in nature. Kinetic investigations suggest that the present system follows pseudo-second-order kinetic model and rate-limiting step is not chemical reaction. The maximum loading capacity of PWR was found to be 116.2 and 39.2 mg g −1 for Pb 2+ and Cu 2+ ions, respectively. FTIR and energy dispersive X-ray analyses supported the sorption of metal ions onto PWR. The results suggested that WR can be an effective adsorbent for the removal of heavy metal ions from aqueous solution.

D‐Galactose based hydrophobic ionic liquid: A new adsorbent for the removal of Cd2+ ions from aqueous solution

“…This lack of consistency proved that the rate limiting step was not chemisorptions, even though the data has been an appropriate fit to the pseudo second order kinetic model. Similar kind of observations was reported for the removal of Pb 2+ and Cu 2+ ions by watermelon rind .…”

Adsorption of Rare Earth Ce3+ and Pr3+ Ions by Hydrophobic Ionic Liquid

“…e inconsistency in the value of k for varying initial concentration of counter ions suggests that chemical reactions are not the rate-limiting step, even though kinetic data tend to fit well with the pseudo-second-order model. Communications observed were similar to this study for the elimination of Cd 2+ ions by ionic liquid [17] and the removal of Pb 2+ and Cu 2+ ions by Watermelon rind [7].…”

“…Adsorption is a premier technique found to be a powerful and cost-effective method for the elimination and recovery of heavy metal ions and precious RREs. Many adsorbents such as activated carbon [ 6 ], agricultural waste and by-products [ 7 ], and organic frameworks [ 8 ] are found to be prolific in terms of cost and being ecofriendly; however, the efficiency and regeneration is always a concerning factor. Recently, the development of nanomaterials and ionic liquids has led to a new era of technological advancements in the field of wastewater treatments and recovery of REEs.…”

Agricultural biomass/waste as adsorbents for toxic metal decontamination of aqueous solutions

“…Watermelon-based biosorbents were also used to adsorb Pb(II) [22,23]. Akkaya and Güzel [23] found that the optimum conditions using watermelon rind as an adsorbent, were obtained at pH 5, 80 min of contact time and 0.1 g/50 mL solid/liquid ratio.…”