DISSOLUTION OF BENZENE IN THE SATURATED POROUS MEDIA

The aim of the present research is to study the dissolution and transport process of benzene as a light nonaqueous phase liquid (LNAPL) in saturated porous media. Unidirectional flow at water velocities ranged from 0.90 to 3.60 cm/hr was adopted to study this process in a three dimensional saturated sand tank (100 cm×40 cm×35 cm). This tank represents a laboratory-scale aquifer. The aquifer was constructed by packing homogeneous sand in the rectangular tank. The experimental results were used to characterize the dissolution behavior of an entrapped nonaqueous phase benzene source in a three dimensional aquifer model. The time invariant average mass transfer coefficient was determined at each interstitial velocity, the values of this coefficient were ranged from 0.016 to 0.061 cm/hr. It was increased proportionally with velocity toward a limiting value. The results show that the concentration of the LNAPL reduces as the distance increased in x and/or z direction from the source of pollution. In most cases the benzene concentration declines with velocity more than 2.34 cm/hr at downstream of the LNAPL pool

DRAG FORCE OF TWO SPHERES IN POWER LAW FLUIDS

The present research is concerned with studying of the drag force on two spheres moving side by side and in line in non-Newtonian liquid. Polyacryamide (PAA) solution with different concentrations (0.01, 0.03, 0.05 and 0.07)% by weight and water is used for comparison for obtaining the effect of fluid properties on the drag force. Different types of spheres stainless steel, glass and plastic with different sizes and densities were used. Within the considered range of power law index (0.6 - 1), and generated Reynolds number (1.1 -75) in power law fluid and Reynolds number (100 - 1000) for water it was found the drag coefficient increases with increasing the power law index for constant generated Reynolds number and the drag force increases with fluid density increases but it decreases with the sphere density increases

REMOVAL OF OIL FROM WASTEWATER BY ORGANOCLAY PREPARED FROM IRAQI BENTONITE

The present study deals with the removal of oil from wastewater by organoclay. The organoclay was prepared by combination of Iraqi bentonite with quaternary amine (hexadecyltrimethyl ammonium chloride). The wastewater samples were obtained from the washing unit of fuel oil in the "South Baghdad Gas Power Plant. The operating conditions of batch process for removal of oil from wastewater by using the prepared organoclays were studied in details (quantity of organoclay, mixer speed and time of adsorption). Initial concentration of wastewater used in this study was within a maximum range of 230-1512 mg/L. XRD and FTIR diagram of the prepared organoclay showed a considerable differences from those for natural bentonite which indicates the exchange of quaternary amine with Ca ions at the surface of bentonite. The concentration of oil in the wastewater samples decreased below 10 mg L after treatment with organoclay. Batch kinetics studies were conducted by using kinetic equations (Lagergren and Ho et al) and batch isotherm studies was conducted by using isotherm models (Freundlich. Langmuir and BET

COMPETITIVE ADSORPTION OF FURFURAL AND PHENOLIC COMPOUNDS ONTO ACTIVATED CARBON IN FIXED BED COLUMN

For a multicomponent competitive adsorption of furfural and phenolic compounds, a mathematical model was built to describe the mass transfer kinetics in a fixed bed column with activated carbon. The effects of competitive adsorption equilibrium constant, axial dispersion, external mass transfer and intraparticle diffusion resistance on the breakthrough curve were studied for weakly adsorbed compound (furfural) and strongly compounds (parachlorophenol and phenol). Experiments were carried out to remove the furfural and phenolic compound from aqueous solution. The equilibrium data and intraparticle diffusion coefficients obtained from separate experiments in a batch absorber, by fitting the experimental data with theoretical model. The results show that the mathematical model includes external mass transfer and pore diffusion using nonlinear isotherms, provides a good description of the adsorption process for furfural and phenolic compounds in fixed bed adsorber.

ESTIMATION OF CRITICAL BED DEPTH IN FIXED BED OFGRANULAR ACTIVATED CARBON

The aim of this study is estimating the critical bed depth in adsorption process through a fixed-bed of granular activated carbon at different bed depths of 0.03, 0.05, 0.08and 0.11m at influent furfural concentration in waste water of 0.2 kg/m3, with constant flow rate of (16.66) × 10-5 m3/min and adsorbent particle size (0.5-1.5) mm. the changing of flow rate and furfural influent concentration had been studied to determine their effects on the critical bed depth value by using bed depth- service time method (BDST). Length of unused bed (LUB) and length of equivalent section of bed had been estimated mathematically during process of the adsorption at different bed depths and during changing the flow rate(8.3× 10-5 m3/min) and influent concentration at same bed depth (0.05m)

REMOVAL OF KEROSENE FROM WASTE WATER USING IRAQI BENTONITE

The aim of the present research is to study the potentiality of Iraqi bentonite as adsorbent for removing of kerosene from wastewater. Also the capacity of bentonite for kerosene removal was compared to the activated carbon capacity. The sorption of kerosene onto bentonite and AC. were described by two well – known adsorption isotherm models namely Langmuir and Freundlich models. It was found that the Freundlich model can fit very well the equilibrium isotherm adsorption of kerosene onto bentonite and AC. Batch experiments were carried out to study the effect of adsorption of kerosene onto bentonite using various conditions such as initial concentrations of kerosene ( 100-500 ) mg/L, agitation speeds (125, 250, 500, 800) RPM, and weights of bentonite ( 0.05, 0.5,1.1 ) gm, particle sizes (0.5- 0.6) mm, and temperature 303 k . It was found that the best results for removing kerosene onto bentonite were obtained at Co=500 mg/L, RPM =800. Activated carbon was used as powder and granular of particle sizes ranged (1-1.18) mm and (0.5-0.6) mm. The results indicated that the activated carbon was more active than bentonite for removing of kerosene from wastewate

Treatment of radioactive liquid waste using Iraqi geological raw materials and zeolite

A radioactive liquid waste contaminated with cesium-137 was found underneath a destructed radioactive waste treatment station in Tuwaytha site 25 km south of Baghdad - Iraq. The appropriate sorbent materials found for the removal of radio cesium-137 were bentonite and modified bentonite with corresponding removal efficiencies of 85% and 91.8% respectively. The favorable batch experimental conditions were found to be 800 rpm stirring speed, 200 mg sorbent mass, 45μm sorbent particle size, and solution temperature of 30 oC for an initial radio cesium concentration of 0.44 mg/l. The BET isotherm model was found to represent the experimental results very well

Removal of Water Turbidity by Different Coagulants

During the last decade, there has been a concern about the relation between aluminum residuals in treated water and Alzheimer disease, and more interest has been considered on the development of natural coagulants. The present study aimed to investigate the efficiency of alum as a primary coagulant in conjunction with mallow, Arabic gum and okra as coagulant aids for the treatment of water samples containing synthetic turbidity of kaolin. Jar test experiments were carried out for initial raw water turbidities 100, 200 and 500 (NTU). The optimum doses of alum, mallow, Arabic gum and okra were 20, 2, 1 and 1 mg/L for100 NTU turbidity level, 35, 4, 2 and 3 mg/L , for 200NTU turbidity level and 50, 8, 10 and 8 mg/L for 500 NTU turbidity level, respectively. The optimum pH was 7 for alum, and 7.5 for mallow, Arabic gum and okra. The residual turbidity was 3.34 to 6.81 NTU by using alum as a primary coagulant with mallow, Arabic gum and okra, and pH values of the treated water by the natural coagulants were 6.1 to 7.01. The optimum dose of the natural coagulants in the present study has higher efficiency in removing high turbidity in comparison with low turbidity. Natural coagulant showed many advantages in coagulation/flocculation process. By using natural coagulants, considerable decreasing in Al2(SO4)3 consumption, and Increasing in the rate of sedimentation can be achieved

Comparative Biosorption Of Pb(II), Cr(III) AND Cd(II) Ions In Single Component System By Live And Dead Anaerobic Biomass, Bath Study

In this study, dead and live anaerobic biomass was used in biosorption of Pb(II), Cr(III) and Cd(II) ions from a synthetic wastewater. The biosorption was investigated by batch adsorption experiments. It was found that, the biosorption capacities were significantly affected by biosorbent dosage. The process follows Langmuir isotherm (regression coefficient 0.995, 0.99 and 0.987 for Pb(II), Cr(III) and Cd(II) ions, respectively, onto dead anaerobic biomass) model with uniform distribution over the biomass surface. The experimental uptake capacity was 51.56, 29.2 and 28 mg/g for Pb(II), Cr(III) and Cd(II), respectively, onto dead anaerobic biomass, compared with 35, 13.6 and 11.8 mg/g for Pb(II), Cr(III) and Cd(II), respectively, onto live anaerobic biomass. The percentage reductions of live compared with dead anaerobic biomass in uptake capacity were 32.3, 53.4 and 57.8 for Pb(II), Cr(III) and Cd(II), respectively. The results indicated that, the dead anaerobic biomass is suitable as an efficient biosorbent for the removal of Pb(II), Cr(III) and Cd(II) ions from wastewater