Super effective recovery of industrial wastewater contaminated by multi-disperse dyes through hydroxyapatite produced from eggshell

The current investigation signified to produce hydroxyapatite (HA) from eggshell via self-combustion route to uptake disperse dyes, Blue 60, Red 152, and Yellow 23, from the industrial single, and multi-contaminated systems. The fabrication process involved subjecting the calcined eggshell powder to nitric acid, and urea solutions followed by heating at 90 degrees C to form a gel for auto-ignition stage. The self-combustion favors to create the meso-porous HA particles with average diameter of 35 nm, leading to achieve a superior adsorption capacity, 520-950 mg g-1, for the removal of disperse dyes from the multi-contaminated system. The lowest adsorption capacity, 520 mg g-1, was determined for the treatment of concentrated wastewater, containing 66.6% blue dye, and the same proportions of red, and yellow dyes, 16.7%. Although the chemical structure of disperse dye could affect the remediation, the adsorption capacity follows the order of blue > red > yellow. The adsorbent performance in the treatment of multi-contaminated systems did not coincide well with the adsorption affinity order. The calcination of fragile powder at 700 degrees C led to create pronounced hydrogen bonds which are beneficial to treat the mentioned wastewater. The excellent thermal stability of fabricated adsorbent provided a condition for the regeneration of contaminated HA which is a promising strategy to reuse in the recovery process, and prevent the generation of secondary pollution.

Automated summary

The study successfully produced hydroxyapatite from eggshell through self-combustion route, demonstrating good adsorption capacity for various disperse dyes in industrial systems. The fabricated adsorbent showed excellent thermal stability and regenerability, providing a promising strategy for reuse in the recovery process.