Coal fly ash for the recovery of nitrogenous compounds from wastewater: Parametric considerations and system design

Sammanfattning

The use of coal fly ash for nutrient recovery in wastewater treatment offers a potential win-win scenario as it simultaneously utilizes and re-channels two wastes - coal fly ash and wastewater. This study investigated the adsorptive recovery of urea from synthetic urine using fly ash. Equilibrium experiments revealed that 1.5 g ash loading, initial urea concentration of 13.5 g L-1, urine pH = 6.0, sorption temperature = 30 degrees C and 150 rpm shaker speed were the optimal process parameters and maximum adsorption capacity was 410 mg g(-1). Proof of concept to the use of synthetic urine was conducted by performing adsorption with real human urine which validated the experimental findings. Comparative analysis and non-linear optimization of nine isotherm models through comprehensive error analysis revealed that Flory-Huggins and Redlich-Peterson equations best described the adsorption. Process thermodynamics suggested that Van der Waal's and electrostatic interactions occur between urea molecules and the surface of fly ash particles; besides, the sorption was found to be exothermic, spontaneous and physical in nature. Kinetic studies pointed toward a pseudo-second-order kinetic fit with contributions from intra-particle diffusion. Further, the rate of mass transfer was seen to be controlled and limited by film diffusion of urea which featured stronger than its pore diffusion. To design a multistage batch adsorber, a mathematical model unique to the sorption system was derived that minimized the total amount of fly ash required for 90% removal of urea from different volumes of influent synthetic urine solutions. (C) 2016 The Authors. Production and hosting by Elsevier B.V. on behalf of King Saud University.

Nyckelord

Resource recovery; Wastewater treatment; Urine; Sustainable waste management; Isotherm analysis; Process design

Publicerad i

Arabian Journal of Chemistry
2019, Volym: 12, nummer: 8, sidor: 5049-5061 Utgivare: ELSEVIER

SLU författare

• Simha, Prithvi

  • Institutionen för energi och teknik, Sveriges lantbruksuniversitet
    
  • University of Manchester

Globala målen

SDG6 Rent vatten och sanitet för alla
SDG12 Hållbar konsumtion och produktion


UKÄ forskningsämne

Vattenbehandling
Vattenbehandling


Publikationens identifierare

DOI: https://doi.org/10.1016/j.arabjc.2016.11.013

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/103839