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Electrocoagulation (EC) dephosphorization kinetics plays an important role in design and amplification of EC reactors for phosphate removal. However, the existing EC dephosphorization kinetic models including both statistical model and adsorption model, fail to establish a direct law between the electric field characteristics and the dephosphorization process, which limit their efficient applications in practice. In this study, three classic adsorption isotherm models, i.e., Langmuir, Freundlich and Dubinin-Radushkevich model, were compared to describe the phosphorus adsorption in EC reactor. The experimental data is better fitted with Langmuir model than the other two models, indicating that adsorbed molecules are monolayered dispersed. Afterwards, an advanced EC dephosphorization kinetic model is developed by combining Faraday's law with Langmuir model. Laundry wastewater is used to illustrate the effects of current densities, plate spacing and initial phosphorus concentrations on the model parameters. Finally, the relationships among current efficiency, current density, plate spacing, initial concentration are established by using response surface methodology. Our new EC kinetic model successfully describe the phosphorus removal process of laundry wastewater, which might pave the way for the optimal design of EC reactor.

The industrial augmentation and unguided anthropogenic activities contaminate water sources in most parts of the world especially in developing countries like Pakistan. High concentration of pollutants in groundwater affects human, soil, and crop health badly. The present study was conducted to investigate groundwater quality for drinking and irrigation purposes in an industrial zone of Pakistan. A GIS tool was used to investigate the spatial distribution of different physico-chemical parameters. In this study, the average results exceeding World Health Organization (WHO) and National Environmental Quality Standards (NEQS) were found for pH 7.84, total dissolved solids (TDS) 1492 mg/L, phosphate 0.51 mg/L, dissolved oxygen (DO) 9.92% saturation, F-coli 6.48 colonies/100 mL, Na+ 366 mg/L, HCO3&minus, 771 mg/L, sulfate 251 mg/L, chlorides 427 mg/L, total hardness (as CaCO3) 292 mg/L, electrical conductivity (EC) 2408 &mu, S/cm, iron (Fe) 0.48 mg/L, chrome (Cr) 0.50 mg/L, arsenic (As) 0.04 mg/L, total phosphorus (TP) 0.17 mg/L, sodium adsorption ratio (SAR) 9.76 (in meq/L), residual sodium carbonate (RSC) 9.28 meq/L, % ion balance 14.4 (in meq/L), percentage sodium ion (% Na+) concentration 58.9 meq/L, and water quality index (WQI) 69.0. The trend of cations and anions were (in meq/L) Na &gt, Mg &gt, Ca &gt, K and HCO3 &gt, Cl &gt, CO3 &gt, SO4 respectively. Although the results of the present study showed poor conditions of the groundwater for drinking as WQI but and irrigation purposes as SAR, it needs to improve some more conditions for the provision of safe drinking water and irrigation water quality.