Laboratory Studies into Tetracycline Removal from Aqueous Solutions by Beads of Calcium-Iron Oxide Nanoparticles

Calcium extraction from chicken bone wastes was utilized for preparing novel sorbent which can use for tetracycline removal in the batch and column experiments. The preparation of sorbent requires to form calcium-iron oxide nanoparticles, and then, they must be immobilized as sodium alginate beads. The nanoparticles were prepared by a precipitation method at best conditions of calcium/iron ratio (Ca/Fe)=1, pH=10, and nano-sized particles mass=5 g per 100 mL. In the batch testing, the removal efficiency was greater than 95%, with ideal conditions including a contact time of 3 h, beads mass of one gram per 50 mL, pH of stock solution 7, and speed of 200 rpm for 100 mg/L initial tetracycline concentration. The sorption of the antibiotic onto sorbent in batch experiments can be best described by Langmuir isotherm with a maximum adsorption capacity of 7.9962 mg/g. Results proved the formation of the dicalcium diiron oxide (Ca2Fe2O5) complex from the reaction of calcium and iron solutions; however, this compound can support the removal of TC from water. The permeable reactive barrier’s ability to control pollutant migration was investigated, and the results show that the barrier longevity can increase dramatically with thicker beds for low values of inlet concentration and water flow rate. Expression of Thomas-BDST was the best model for simulating the outcomes of continuous experiments.