Competitive Adsorption of Methylene Blue and Cu²⁺ onto Citric Acid Modified Pine Sawdust

Abstract

Pine sawdust modified with citric acid (CA‐PS) is used as an adsorbent for the removal of Cu2+ and methylene blue (MB) from the single and binary compound systems. The initial pH has a significant effect on Cu2+ adsorption, but a relatively little effect on MB adsorption. The kinetic and isotherm studies indicate that the pseudo‐second‐order model and the generalized model provide the best correlation of the experimental data in the single systems as well as in the binary systems. The adsorption capacities of CA‐PS from Generalized isotherm model are 0.23 mmol/g for Cu2+ and 0.25 mmol/g for MB, which are higher than that of B‐PS. In the binary systems, Cu2+ and MB exhibit competitive adsorption behaviors. The adsorption capacity of Cu2+ or MB is considerably reduced with an increase in the concentration of the other, and Cu2+ exhibits better competiveness than MB. However, the total adsorption capacity is higher compared with that in the single systems, which increases with an increase in the initial concentration of Cu2+ or MB and reaches a plateau value of 0.301 mmol/g.

Ultrasonic treatment of textile dye effluent utilizing microwave‐assisted activated carbon

“…6 Further, percent removal was calculated and adsorptive capacity were reported. 49 The percent removal was calculated as, 26 %Removal = Co−Ce Co *100 ð1Þ…”

Adsorption of heavy metals and methylene blue from aqueous solution with citric acid modified peach stone

“…Then these dried peach stones were milled and sieved to obtain 50-60 mesh fractions (labeled as PS). To increase the proportion of active surfaces and to inhibit tannin compounds [20] , twenty grams of sieved peach stones were soaked in 400 ml of 0.1 M NaOH and stirred in a magnetic stirrer for 1 h at room temperature. Then the soaked peach stones were rinsed several times with deionized water to remove excess base until the pH reached approximately to neutral, dried overnight at 50℃ in the oven (labeled as BPS) and stored in plastic bags for the following experiments.…”

“…Nowadays, citric acid as a good modificator has been used to increase the contents of carboxyl group through esterification reaction [17] . Meanwhile, some literatures have reported that agricultural materials such as barley straw [18] , corncob [19] and pine sawdust [20] modified with citric acid had excellent adsorption efficiency for heavy metals and MB.…”

Current Advances of Polymer Composites for Water Treatment and Desalination

“…Hence, there was an electrostatic interaction between the positive copper ions and the negative charges of the composite. Moreover, the hydroxyl groups contributed to the adsorption of copper ions through a hydrogen bonding network [32].…”