Effect Of Sorption Time Research Articles

Biosorption of chromium (VI+) using tamarind fruit shells in continuously mixed batch reactor

<p>The locally available tamarind fruit shells (TFS) pre-treated with 1N H3PO4 was used to remove the hexavalent chromium (Cr6+) from aqueous phase. The investigation was done by using continuously mixed batch reactor (CMBR) under room temperature. Few preliminary investigations was undertaken to optimize the system parameters of the Cr6+ PATFS system. The batch studies cover the important experiments such as biosorption kinetics, biosorption equilibrium isotherm, effect of pH, effect of ionic strength, and effects of the presence of other anions in the system on biosorption of Cr6+. From preliminary investigation, the PATFS revealed a highest efficacy (99.1%) in removing Cr6+ from aqueous phase, apart from other pre-treated TFS. It was revealed that the density and mechanical properties of the treated and untreated composites increased with the decrease in the particle size; whereas, the water absorption percentage and void content decreased for the same. (a) Effect of heavy metal concentration on the sorption capacity. (b) Effect of solution pH on the sorption capacity. (c) Effect of sorption temperature on the sorption capacity. (d) Effect of sorption time on the sorption capacity. At a concentration of 50 mg/l of Cr6+, more than 95% was appeared to be removed by 12 g/l of 0.13 mm (geometric mean size) of PATFS. The biosorption kinetics of Cr6+ was modeled by using integrated rate expression and second order rate constants were determined for different Cr6+concentrations. Uptake of Cr6+on PATFS was well described by Freundlich isotherm for different biosorbent sizes. UV-VIS spectrophotometer was used to measure the concentration of Hexavalent chromium in water. The desorption study was also carried out and it’s significant by 0.5H2SO4.</p>

Study of Acid Treated Mixed Sawdust as Natural Oil Sorbent for Oil Spill

Despite the presence of many techniques to clean up oil spills, sorbents are considered as one of the most attractive techniques due to the high rate of absorption or adsorption and ease of application. Organic-based sorbents have become the best type to use based on their abundance of resources and its biodegradability. Among the many natural organic sorbents available, sawdust has big potential to be used as oil absorbent due to its advantages of being low-cost source, low density and exhibiting hydrophobic-oleophillic characteristics. In this study, the utilization of mixed sawdust as oil sorbent was investigated. The mixed sawdust sorbent was treated using chemicals such as ethanol, sodium hydroxide and hydrochloric acid to further improve the efficiency for oil absorbency. The performance of as-prepared and acid-treated sorbent was characterized using sorption capacity (g/g). The effects of sorption time and surface condition (on seawater surface or on land) towards the performance of sorbent was then investigated. Besides that, the temperature, oil viscosities and reusability of treated sawdust were also studied. It has been proven that acid treated sawdust has higher sorption capacity of 4.82 g/g even after 90 minutes of sorption with four times reusability due to improved hydrophobic and oleophillic characteristics. It was also found that the viscosity of oil and temperature can also affect the sorption capacity. Crude oil, which poses lower viscosity (30.51cP) and at oil temperature of 27°C gave the highest sorption because of the migration of oil into the structure of sorbent was accelerated. This study indicated the possibility of using sawdust as sorbent for oil spill control.

Removal of Cu (II) from aqueous solutions using magnetite: A kinetic, equilibrium study

Water pollution means that the physical, chemical and biological properties of water are changing. In this study, adsorption was chosen as the treatment method because it is an eco-friendly and low cost approach. Magnetite is a magnetic material that can synthesize chemical precipitation. Magnetite was used for the removal of copper in artificial water samples. For this purpose, metal removal from water dependent on the pH, initial concentration of metal, amount of adsorbent and effect of sorption time were investigated. Magnetite was characterized using XRD, SEM and particle size distribution. The copper ions were determined by atomic absorption spectrometry. The adsorption of copper on the magnetite was studied in a batch process, with different aqueous solutions of Cu (II) at concentrations ranging from 10 to 50 mg l-1. Optimum conditions for using magnetite were found to be concentration of 10 mg L-1, pH: 4.5, contact time: 40 min. Optimum adsorbent was found to be 0.3 gr. Furthermore, adsorption isotherm data were analyzed using the Langmuir and Freundlich equations. The adsorption data fitted well with the Freundlich (r2 = 0.9701) and Langmuir isotherm (r2 = 0.9711) equations. Kinetic and equilibrium aspects of the adsorption process were studied. The time-dependent Cu (II) adsorption data were described well by a pseudosecond-order kinetic model.

Investigation of the Microcellular Foaming and Diffusion of Supercritical Carbon Oxide in the Polypropylene/TiO2 Nanocomposites

The nanocomposites composed of polypropylene (PP) and TiO2nanoparticles with uniform dispersion (PP/TiO2nanocomposite) were prepared. The effects of the content of TiO2nanoparticles on the crystallinity of PP and the sorption amount (Ms) of CO2in PP/TiO2nanocomposite were investigated. The crystallinity of PP increased when the content of TiO2was less than 2wt% and decreased Subscript text when the content was over 2wt% (Msof CO2decreased when the content of TiO2nanoparticles was less (2increased from 3 wt% to 5 wt%. The effects of sorption time, extended ranges of temperature and pressure on Msof CO2were also studied by gravimetric method. The mechanism of the sorption and desorption of supercritical CO2in the PP/TiO2nanocomposite was discussed. In addition, the pore density of the microcellular PP/TiO2nanocomposite was controllable by tuning the Ms of CO2.

Characterization of Activated Carbon and Application of Copper Removal from Drinking Water

In this study, removal of copper ions from aqueous solution by adsorption was investigated. The methods were applied to removal of copper in artificial water and drinking water samples using activated carbon. For this purpose, metal removal from water depends on the pH, initial concentration of metal, amount of activated carbon, and effect of sorption time were investigated. The process parameters were investigated with batch studies. In this study, commercial activated carbon, Chemviron C-1300, has been used. Granular activated carbon were characterized using nitrogen porosimetry, pH titration, Boehm's titration, mercury porosimetry, FTIR and scanning electron microscope measurements. The copper ions were determined by an atomic absorption spectrometry. Optimum conditions were found as concentration of 10 mg l-1, pH: 5, contact time:25 min, and activated carbon amount:750 mg. Optimum condition were applied to drinking water for removal of Cu(II). Furthermore, adsorption isotherm data were fitted to both Langmuir and Freundlich models for finding the optimum conditions.

Characterization of Activated Carbon and Application of Copper Removal from Drinking Water

AbstractIn this study, removal of copper ions from aqueous solution by adsorption was investigated. The methods were applied to removal of copper in artificial water and drinking water samples using activated carbon. For this purpose, metal removal from water depends on the pH, initial concentration of metal, amount of activated carbon, and effect of sorption time were investigated. The process parameters were investigated with batch studies. In this study, commercial activated carbon, Chemviron C‐1300, has been used. Granular activated carbon were characterized using nitrogen porosimetry, pH titration, Boehm's titration, mercury porosimetry, FTIR and scanning electron microscope measurements. The copper ions were determined by an atomic absorption spectrometry. Optimum conditions were found as concentration of 10 mg l‐1, pH: 5, contact time:25 min, and activated carbon amount:750 mg. Optimum condition were applied to drinking water for removal of Cu(II). Furthermore, adsorption isotherm data were fitted to both Langmuir and Freundlich models for finding the optimum conditions.

Preparation of porous polysulfone beads for selective removal of endocrine disruptors

Porous polysulfone (PSf) beads are prepared using a liquid–liquid phase separation technique. The porous PSf beads are then used for the removal of endocrine disruptors, such as Biphenyl (BP), dibenzofuran (DBF), dibenzo- p-dioxin (DBD), biphenol A (BPA), and diethylstylbestrol (DES) from their aqueous solutions. The endocrine disruptors could be removed efficiently by a simple sorption method with hydrophobic porous PSf beads. The removal ratio was high for endocrine disruptors having high octanol–water distribution coefficients. The effect of sorption time, weight of PSf beads, ethanol amount in the solution, and the porosity of the beads on the removal of endocrine disruptors was investigated. The adsorbed endocrine disruptors in the PSf beads could be effectively removed by 2-propanol or ethanol, which indicated that the beads could be reused. The study suggested that the porous PSf beads have a potential ability to be used for the removal of endocrine disruptors in environmental application.

An empirical relationship between distribution coefficients of phenols by polyurethane foams and their octanol–water distribution constants and p Ka values

Sorption of phenol, 3-cresol, 2-, 3-, 4-nitrophenols, 2,4-, 2,6-dinitrophenol, 2,4,6-trinitrophenol, and 1-naphthol by polyether- and polyester-type polyurethane foams (PUF) was investigated. The effects of sorption time, pH, phenol concentration and the structure of tested phenols and PUF were studied. The mechanism of sorption of tested compounds on foams is discussed. It is shown that the hydrophobicity (log P, octanol–water distribution constant) and p K a values of the compounds play an important role in the sorption process. A regression equation connecting distribution coefficient of phenols by PUF with their hydrophobicity parameter and p K a values were derived. Good correlation between log D and values log P and p K a was observed.