Ahmed A. Mohammed

Competitive biosorption of lead, cadmium, copper, and arsenic ions using algae.

The present study aims to evaluate the competitive biosorption of lead, cadmium, copper, and arsenic ions by using native algae. A series of experiments were carried out in a batch reactor to obtain equilibrium data for adsorption of single, binary, ternary, and quaternary metal solutions. The biosorption of these metals is based on ion exchange mechanism accompanied by the release of light metals such as calcium, magnesium, and sodium. Experimental parameters such as pH, initial metal concentrations, and temperature were studied. The optimum pH found for removal were 5 for Cd2+ and As3+ and 3 and 4 for Pb2+ and Cu2+, respectively. Fourier transformation infrared spectroscopy analysis was used to find the effects of functional groups of algae in biosorption process. The results showed that Pb2+ made a greater change in the functional groups of algal biomass due to high affinity to this metal. An ion exchange model was found suitable for describing the biosorption process. The affinity constants sequence calculated for single system was KPb > KCu > KCd > KAs; these values reduced in binary, ternary, and quaternary systems. In addition, the experimental data showed that the biosorption of the four metals fitted well the pseudo-second-order kinetics model.

Removal of lead, cadmium, copper, and arsenic ions using biosorption: equilibrium and kinetic studies

Abstract Biosorption of lead, cadmium, copper, and arsenic ions by using native algae was investigated. Experiments were carried out in a batch reactor to obtain equilibrium and kinetic data. Experimental parameters affecting the biosorption process such as pH, shaking time, initial metal concentrations, and temperature were studied. The optimum pH for removal was found to be 3, 5, 4, and 5 for Pb2+, Cd2+, Cu2+, and As3+, respectively. Biosorption of these metals is based on ion-exchange mechanism accompanied by release of light metals such as calcium, magnesium, potassium, and sodium. Experimental isotherms data well fitted an ion-exchange model and the affinity constant was calculated for each metal. The results showed the ion-exchange model was found suitable for describing the biosorption process. Fourier Transformation Infrared Spectroscopy analysis was used to find the effects of functional groups of algae in biosorption process. The results showed that Pb2+ had a greater difference in the peak valu...

Comparative Study of Removal of Cadmium (II) and Chromium (III) Ions from Aqueous Solution Using Low-Cost Biosorbent

Abstract This study aims to evaluate the ability of abundant low-cost garden grass to remove cadmium and chromium ions from aqueous solutions. Batch biosorption studies were carried out to examine the biosorption capacity, pH value, temperature, agitation speed, and metal ions concentration. The biosorption process revealed that the garden grass was an effective biosorbent of cadmium and chromium. The maximum chromium and cadmium removal rate was 90 and 80% at pH 4, respectively. FTIR spectroscopy analysis showed that the hydroxyl, amine, and carboxyl groups were the major groups responsible for the biosorption process. The maximum biosorption capacity was 18.19 and 19.4 mg/g for cadmium and chromium, respectively. The biosorption isotherm data fitted well the Langmuir model. Kinetic data were adequately fitted by the pseudo-second-order kinetic model.

Column Biosorption of Lead, Cadmium, Copper, and Arsenic ions onto Algae

A mixture of green and blue-green algae was used as an adsorbant material for biosorption of lead, cadmium, copper, and arsenic ions in fluidized bed reactor. Batch experiments showed that the algal biomass was successfully used for the removal of these metal ions from wastewater. The maximum percentage removal for 1 g dose was 89, 82, 79, and 70 for Pb2+, Cu2+, Cd2+ and As3+, respectively. The experimental data fit well to an ion exchange equilibrium model. Affinity constants were calculated for each metal. A higher affinity of the biomass towards lead (Pb2+) was observed due to the high electronegativity of this metal. FTIR analyses showed that hydroxyl and carboxyl groups could be very effective for capturing these metals. An ideal plug flow model was adopted to characterize the fluidized bed reactor and solved numerically using MATLAB version (R2009b), which fit well to the experimental breakthrough data. The effects of different operating conditions such as: static bed height, superficial velocity and particle diameter on the removal process were investigated. Lead showed the largest operating time compared with others.

Separation and Hydrodynamic Performance of Air-Kerosene-Water System by Bubble Column

The separation of emulsified kerosene in water (concentration 250-750ppm) was investigated in a bubble column15.6 cm diameter and 120 cm height. The effective behaviors of bubble characteristics (bubble diameter, bubble rise velocity and air hold-up) on the removal efficiency were measured by electroresistivity probe. The effects of kerosene concentration, air flow rate,bubble diameter, liquid height, liquid viscosity, NaCl concentration, and alum on the removal rate were found. The experimental results showed that the removal efficiency increased with increasing air flow rate (1.09-2.6cm/s) and decreased with increasing CMC concentration. The results also showed that adding anionic surfactants (SLES and SDBS) leads to increase removal rate. The the flotation process was found to be first order kinetics. New correlations of air holdup and bubble diameter using dimensionless groups were derived.

Biosorptionof Cadmium Ions ontoGarden Grass

The garden grass was utilized as low cost adsorbent to remove cadmium ions from aqueous solution usingbiosorption. All the experiments were conducted in batch system to investigate the biosorption capacity as well as the effects of pH, temperature, agitation speed, and initial metal concentration on the biosorption efficacy. Fourier Transformation Infrared Spectroscopy analysis was used to find the effectsof functional groups of garden grass in biosorptionprocess. The results showed that the garden grass could be used efficiently to remove cadmium from aqueous solution and up to 85% of cadmium removal was obtainedat the optimal conditions. The biosorption equilibrium was reached at 60 min and the maximum biosorption capacity was found to be 17.2 mg/g for 1 g dose.Experimental isotherms data well fittedthe Langmuir model. Experimental kinetics data showed that the biosorption process fitted well the pseudo-second-order kinetics model.