Ligand-based poly(phenylenediamine) adsorbents for enhanced removal of phosphate from water

• Published in: Polymer bulletin (Berlin, Germany) Vol. 79; no. 10; pp. 8743 - 8763
• Main Authors: Mdlalose, Lindani, Balogun, Mohammed, Setshedi, Katlego, Klavins, Maris, Chimuka, Luke, Chetty, Avashnee
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.10.2022; Springer Nature B.V
• Subjects: Adsorbents; Adsorption; Caustic soda; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Complex Fluids and Microfluidics; Eutrophication; Fourier transforms; Lewis acid; Ligands; Mass transfer; Organic Chemistry; Original Paper; Oxidation; Oxidizing agents; Phenylenediamine; Phosphates; Phosphorus; Phosphorus removal; Physical Chemistry; Polymer Sciences; Polymerization; Polymers; Potassium; Potassium dichromate; Sodium; Soft and Granular Matter; Sorbents; Spectrum analysis; Synthesis; Phosphates; Regeneration; Poly(phenylenediamine) isomers; Adsorption; Inner-sphere complexing
• ISSN: 0170-0839; 1436-2449
• DOI: 10.1007/s00289-021-03922-4

Phosphorus removal from effluents is vital to avoid eutrophication. The subject study presents the development and performance of poly(phenylenediamine) isometric adsorbents produced through oxidation using (NH 4 ) 2 S 2 O 8 and K 2 Cr 2 O 7 oxidants. K 2 Cr 2 O 7 synthesized polymers showed better adsorption capacities. The presence of Cr Lewis acid on the surface endorsed phosphate interaction through inner-sphere complex mechanism. The maximum adsorption capacities for K 2 Cr 2 O 7 synthesized polymers were 143, 217 and 69.0 mg/L for poly( o -phenylenediamine), poly( m -phenylenediamine) and poly( p -phenylenediamine) adsorbents, respectively. The superior performance of poly( m -phenylenediamine) was associated with minimal symmetrical arrangement, hence it was more amorphous as indicated by XRD patterns. Kinetic model fitted pseudo-second-order and isotherm favoured Langmuir. Adsorption process was also controlled by pore diffusion and external mass transfer in the sorbent. Poly( m -phenylenediamine) displayed high affinity in the presence of competing anions and was amenable to recycling.