A comparison was made of the linear least-squares method and a trial-and-error non-linear method of the widely used pseudo-second-order kinetic model for the sorption of cadmium onto ground-up tree fern. Four pseudo-second-order kinetic linear equations are discussed. Kinetic parameters obtained from the four kinetic linear equations using the linear method differed but they were the same when ...

Molecular modeling techniques were used to establish relationships between the molecular properties of 45 substituted phenylureas and their octanol/water partition coefficient (log P) and soil sorption normalized to organic carbon (Koc). Log P and Koc values were obtained from the literature. The molecular properties were calculated using MOPAC-MNDO molecular orbital methods. The OSAR models ba...

Soil column studies are used frequently in seeking to understand the behavior of a particular contaminant in a saturated homogeneous soil of a given type. The concentration of the contaminant is modeled by a parabolic partial differential equation. We seek to identify the sorption partitioning coefficient as a function of time from limited boundary data. We discuss an output least squares formu...

While the small sticking coefficient for molecular hydrogen on the Si(001) surface apparently requires a large energy barrier of adsorption, no such barrier is observed in desorption experiments. We have calculated the potential-energy surface of an H 2 molecule in front of a Si(001) surface. If we relax the Si substrate, we find an optimum desorption path with a low (< ∼ 0.3 eV) ad-sorption en...

Zirconium tungstate as an inorganic ion exchange material has been synthesized at different conditions. The materials were characterized by means infrared spectroscopy, thermo gravimetric analysis, and X-ray diffraction techniques. The stability of the ion exchangers was investigated in acidic and alkaline media. Ion exchange properties of synthesized materials were studied by measuring the dis...

The exchange of malic acid, lactic acid, NaCl, and sugar between cucumber and cover brine was monitored over a course of 16 days for 5 sizes of cucumbers. Experimental results showed that sugar exchange between cucumbers and cover brine was the slowest. In comparison to Ficks diffusion equation, the exponential equation better described the movement of solutes during the brine fermentation of c...

Soil aggregates were prepared from a bulk soil collected from paddy soil in the Taihu Lake region and aluminum (Al) dissolution, solution pH changes during copper (Cu(2+)) sorption were investigated with static sorption and magnetic stirring. Kinetics of Cu(2+) sorption and Al dissolution were also studied by magnetic stirring method. No Al dissolution was observed until Cu(2+) sorption was gre...

Algae are widely used as biosorbent for the sorption of heavy metals, however sorption of oil on algae has not been explored. Algae in marine and fresh water environment may affect the fate and transport of spilled oil. Sorption of diesel and lubricating oil was studied using dead biomass of Spirulina sp. and Scenedesmus abundans. The rate and extent of sorption was studied in well mixed batch ...

In this work, removal of C. I. Acid Red 14 was investigated by Pumice stone as a low cost adsorbent. Various parameters such as initial dye solution, contact time and pH were studied. Removal of dye were increased by increasing of contact time and initial dye solution and deceased by increasing of pH. Three isotherm models were studied. Linear and non-linear regression analyses were used fo...

Hydraulic conductivity and sorption coefficients for chlorinated hydrocarbons (chloroform, carbon tetrachloride and tetrachloroethylene) were evaluated for 216 sediment samples collected across a 15 m transect and a 21 m depth interval in a contaminated aquifer near Schoolcraft, Michigan. Relationships between hydraulic conductivity, linear sorption partition coefficients, grain size classes, a...