الفهرس 
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Abstract
Biosorption removal of nitrogen, phosphorus and heavy metal ions utilizing biological substances has been significantly explored in the last decade owing to its possibility, particularly in wastewater treatment. The present study aimed to describe the effectiveness of microalga Chlamydomonas sp. as fresh biomass for disposing of nitrogen, and phosphorus from wastewater and dried biomass for heavy metals as arsenic and cadmium from an aqueous solution. The study included studying the effect of some factors on the adsorption capacity of the studied microalgae (optimization study), such as initial concentrations of heavy metal sequence (25, 50, 100, 140, 180, 200 mgl-1), biosorbent doses (0.2, 0.4, 0.6, 0.8, 1, 1.2 gl-1), pH (3, 4, 5, 6, 7, 8), temperature (15, 20, 25, 30, 35, and 40 ℃) and contact time (10:160) min. All trials were performed at a shaking speed of 300 rpm. The optimization study indicated a pH of 4, a heavy metal concentration of 50 mgl-1, a contact time of 60 min, a temperature of 25 °C, and a biomass concentration of 0.6 gl-1 were the best optimum conditions for the bioremediation activity for arsenic heavy metal. The optimum and ideal conditions for biosorption activity for cadmium were found at, pH 4, a heavy metal concentration of 50 mg/l, a contact period of 60 min, a temperature of 25 °C, and optimum biomass of 0.8 g/l. The maximum removal percentages were 71.8 %, 69.5 %, 95.2 % and 95.6 % for nitrogen, phosphorus, arsenic and cadmium, respectively. The biosorption capacity of arsenic and cadmium was 53.8 mg/g and 44.75 mg/g, respectively. Also, the biosorption process was evaluated and characterized using Fourier transform infrared, X-ray diffraction, scanning electron microscope, dynamic light scarring, and zeta potential. Kinetics, isotherm equilibrium. In addition, the thermodynamics characterization was conducted to describe the feasible biosorption rate and maximum biosorption capacity of the biosorbent.