On the removal efficiency of copper ions in wastewater using calcined waste eggshells as natural adsorbents

Abstract

Eggshells offer many advantages as adsorbents, such as affordability without special preparations other than pulverization and calcination. However, the manufacturing industry generally has a severe problem with high concentrations of heavy metals in wastewater. The purpose of this study was to use eggshell byproducts and calcined eggshell treatment for the adsorption of copper in an aqueous solution. The reaction time, metal concentration, adsorbent dose, temperature, and pH were evaluated using primary factors followed by the response surface method (RSM) to investigate the optimum conditions for eggshell byproducts and calcined eggshell adsorption treatment. The results of the one-factor-at-a-time experiment showed that the optimal adsorption rate was obtained from treatment at 24 h, 25 mg/L, 10 mg, and 25 °C. In addition, the effect of pH on the adsorption rates of eggshells and eggshells with membrane were detected at pH values of 5 and 5.9 and found to be 95.2, 90.5, and 73.3%. The reaction surface experiment showed that the best adsorption rate reached 99.3% after calcination at 900 °C for 2 h and a 20 min reaction. The results showed that eggshells, eggshell membranes, eggshells with membrane, and calcined eggshells could be applied to remove copper ions from industrial wastewater. The adsorption capacity of the calcined eggshell is better than that of the non-calcined eggshell and has good neutrality in acidic industrial wastewater. Therefore, it is convenient and practical for practical production and application. Likewise, this study conveys promising findings in the context of improving wastewater treatment based on a circular economy approach to waste reuse in the food industry and represents a valuable direction for future research.

Preparation of Molybdenum Disulfide with Different Nanostructures and Its Adsorption Performance for Copper (Ⅱ) Ion in Water

“…The results showed that the adsorption capacity increased with an increase in temperatures (20–80 °C). This may be attributed to the accelerated diffusion rate and increased effective active sites [ 48 ]. When the adsorption temperature rises from 80 °C to 100 °C, the adsorption capacity decreases, which may be due to the destruction of adsorption equilibrium, the enhancement of the desorption process, and the intensification of molecular movement above 80 °C.…”

Characterization of activated carbon produced from the green algae Spirogyra used as a cost-effective adsorbent for enhanced removal of copper(ii): application in industrial wastewater treatment

“…Commercial activated carbon is available but it is expensive and not economically viable, 4 prompting a search for cheaper and more efficient alternatives. Recently, a wide variety of raw materials that are abundant in nature have been used to prepare porous materials that have been converted into low-cost activated carbon for copper removal, such as beech wood chips and garden green waste residues, 20 palm fiber, 21 soy waste, 22 peanut shells, 6,23 soybean and mustard husks, 10 walnut shells, 24 waste wood-based panels, 15 olive stone, 25 pigeon peas hulls, 26 apple tree branches, 5 lignites, 27 waste tea residue, 13 eggshells, 28 oak fruit shells, 29 sea mango shells, 30 wolfberry stems 31 and empty fruit bunches. 32 The adsorption capacity of these adsorbents is high and the research is still focused on looking for low-cost adsorbents that are abundant in nature to improve the efficiency.…”