Comparing Adsorption Properties of Algerian Kaolinite Towards Phosphate with Those of Activated Carbon: Adsorption Experiments, Molecular Modeling and an Initiative Toward Hydroponic Wastewaters Remediation

• Published in: Water, air, and soil pollution Vol. 235; no. 7; p. 422
• Main Authors: Fizir, Meriem, Richa, Amina, Touil, Sami, Fermous, Rachid, Tahir, Chahinez, Hassene, Imane, Wei, Liu, Douba, Houda
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.07.2024; Springer Nature B.V
• Subjects: Activated carbon; Activated clay; Adsorbents; Adsorption; Aqueous solutions; Atmospheric Protection/Air Quality Control/Air Pollution; Chemisorption; Climate Change/Climate Change Impacts; Contamination; Earth and Environmental Science; Environment; Experiments; Fourier transforms; Heterogeneity; Hydrogeology; Hydroponics; Infrared spectroscopy; Kaolinite; Kinetics; Molecular modelling; Phosphate; Phosphates; Phosphorus removal; Soil Science & Conservation; Wastewater treatment; Water Quality/Water Pollution; X-ray diffraction; Kaolinite; Adsorption; Activated carbon; Phosphate
• ISSN: 0049-6979; 1573-2932
• DOI: 10.1007/s11270-024-07235-w

In this research, adsorption properties of an Algerian kaolinite (KNTs) for removal of phosphate from aqueous solutions was compared with those of a commercial activated carbon (AC) in term of kinetics, equilibrium, and thermodynamic studies. Fourier Transform Infrared (FTIR) spectroscopy and X-ray diffraction (XRD) was used to characterize the adsorbants. Effect of various reaction parameters such as pH, adsorbent dose, adsorption time, and temperature on PO 4 3− adsorption by both adsorbents were explored and compared. Adsorption experiments showed that KNTs is a good adsorbent of phosphate. However, it is not superior to AC in terms of adsorption capacity. The maximum uptake capacity of AC and KNTs (71.89 and 16.93 mg/g) have been reached after 60 and 250 min, respectively. The two adsorbents showed a higher phosphate removal rate of 93.74% for AC and 69% for KNTs. The pH of the solutions, affect considerably the adsorption mechanism. The removal capacity results of PO 4 3− by KNTs showed significant fit with both pseudo-first-order and pseudo-second-order models proving the dominance of both physisorption and chemisorption mechanisms during the uptake of phosphate. Whereas, the adsorption of PO 4 3− by AC found to be controlled by physisorption only. Isotherm simulation studies of the adsorbents showed that KNTs presented high heterogeneity degree than AC and the adsorption of phosphate is well described by Temkin model. Adsorption/desorption experiments suggested that KNTs could be successfully regenerated in multiple times (at least three). Based on theoretical calculations, different configurations of KNTs@PO 4 3− were obtained after minimizing their energy using MM2 Server. The later revealed that phosphate with more charged (HPO 4 2− ), showed greater interaction energy than H 2 PO 4 − , which indicated that HPO 4 2− interaction with KNTs are more stable. The adsorption experiments in real hydroponic wastewaters further indicated the application potential of KNTs. This research offered potential candidate (Algerian kaolinite) for water cleaning up against phosphate contamination.