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Wastewater flocculation using a new hybrid copolymer: modeling and optimization by response surface methodology

100%

Dawood A. S. , Li Y.

Polish Journal of Environmental Studies

2014

tom 23

nr 1

A new hybrid inorganic-organic copolymer, aluminum chloride-poly(acrylamide-co-acrylic acid), was prepared using the free radical polymerization method and employed in this study. The hybrid copolymer was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy-dispersive x-ray spectroscopy (EDS). This hybrid copolymer was used in the flocculation of wastewater as a new flocculant. The design variables in the flocculation experiments were hybrid copolymer dosage and wastewater pH. The central composite design (CCD) for the response surface methodology (RSM) approach was used to develop a mathematical model and to optimize the parameters of the flocculation process in terms of optimal removal of chemical oxygen demand (COD), total suspended solids (TSS), and turbidity. After applying the analysis of variance (ANOVA) of all quadratic models, it was found that the obtained value of the correlation coefficient (R2) was more than 0.98 for all models. The optimum hybrid copolymer dosage was 125 mg/l and the optimum pH 7.55. Under these optimum values, the wastewater treatment achieved 97%, 98.6%, and 88.6% removal of turbidity, TSS, and COD, respectively.

Simultaneous removal of NH4+ and PO43- from simulated reclaimed waters by modified natural zeolite. Preparation, characterization and thermodynamics

80%

Alshameri A. , He H. , Dawood A. S. , Zhu J.

Environment Protection Engineering

2017

tom Vol. 43, nr 4

73--92

Natural zeolite was modified by NaCl, AlCl3 and thermal treatment for the removal of NH4+ and PO43− ions. The characteristics of the modified zeolite (AlZ) and its mechanism for the NH4 + and PO43− removal were studied and compared. The results showed that the surface area and the Na+ and Al3+ content increased whereas the content of Ca2+, K+ and Mg2+ decreased after zeolite modification. On natural zeolite when activated with the 1 M NaCl and 10 cm3 /g of pillaring dosage, high adsorption efficiencies for the NH4 + (97.80%) PO43− (98.60%) were obtained. The results of various analyses indicated that the Na+ exchange is the main mechanism for NH4 + removal whereas the adsorption mechanism for PO43− followed the complexation with Al–OH groups present in the AlZ. In addition, the kinetics study showed that the adsorption of NH4+ and PO43− followed pseudo-second order model while the adsorption isotherm of NH4 + and PO43− is consistent with the Langmuir isotherm model. Moreover, the Gibbs free energy change for the simultaneous removal of the ions indicates that NH4 + is adsorbed faster compared to PO43−. The simultaneous removal of NH4 + and PO43− by AlZ adsorbent is cost effective in water treatment at low ion concentrations.