Ayoup M. Ghrair

Bioremediation of cadmium-contaminated water systems using intact and alkaline-treated alga (Hydrodictyon reticulatum) naturally grown in an ecosystem

ABSTRACT Cadmium can enter water, soil, and food chain in amounts harmful to human health by industrial wastes. The use of intact and NaOH-treated dried algal tissues (Hydrodictyon reticulatum), a major ecosystem bio-component, for Cd removal from aqueous solutions was characterized. Cadmium biosorption was found to be dependent on solution pH, bioadsorbent dose, the interaction between pH and dose, contact time, and initial Cd concentration. The experimental results indicated that the biosorption performance of alkaline-treated algal tissues was better than that of intact tissues. The maximum biosorption capacities were 7.40 and 12.74 mg g−1 for intact and alkaline-treated bioadsorbents, respectively, at optimum operating conditions. Biosorption reaches equilibrium after 24 and 240 minutes of contact, respectively, for alkaline-treated and intact bioadsorbents. Cadmium biosorption was best fitted to Langmuir isotherm model (R2 ≈ 0.99) and the kinetic study obeyed the pseudo-second-order kinetic model, which suggests chemisorption as the rate-limiting step in the biosorption process. Alkaline-treated algal tissues can be used as a new material of low-cost bioadsorbent for continuous flow rate treatment systems.

An efficient sorbent for phosphate removal from wastewater: a new application of phosphate mine wastes from Ruseifa City—Jordan

AbstractJordanian phosphate mine wastes (PMW) at Ruseifa City was fully characterized and tested for its PO4 removal capacity by batch experiments using prepared phosphate solutions and domestic wastewater. PMW particles are positively charged with median particle size of 0.625xa0μm. Mineralogical and chemical analyses of PMW showed that it is mainly composed of calcite, fluorapatite, and quartz with high concentrations of calcium and phosphorous. The phosphate concentrations in PMW range from 11 to 24% expressed as P2O5. PMW as a sorbent has a very high PO4 removal efficiency from wastewater and prepared solutions. PO4 solutions with concentrations ranging from 5 to 5,000xa0mgxa0L−1 were prepared and utilized in batch experiments in the presence of PMW as a sorbent. The concentration of PO4 in the solution phase and pH were the main parameters influencing the PMW sorption capacity of PO4. The PO4 removal efficiency from prepared solutions was up to 99%. Moreover, Langmuir sorption model was able to describe th...