Henry Setiyanto

First-Principles Calculations for Chemical Reaction between Sodium Diethyldithiocarbamate and Transition-Metal (Cr) atom to Produce Cr(DDC)3 and Cr(DDC)2ODDC

We investigate the chemical reaction between a Cr transition-metal atom and sodium diethyldithiocarbamate (NaDDC), a complexing agent used to detect and extract Cr in human blood samples. Using density-functional-theory-based calculations, we determine their stable structures of Cr(DDC)2ODDC and Cr(DDC)3 complexes and obtain their dissociation energies. We found dissociation energies of -10.66 and -3.24 eV for Cr(DDC)2ODDC and Cr(DDC)3 complexes, respectively. Hence, on the basis of dissociation energies, we have verified that the reaction of NaDDC with Cr produces Cr(DDC)2ODDC as a major product.

The removal of nickel, copper and cadmium from aqueous solution using liver moss (Dumortiera hirsute Sw. nees)

The aim of this study was to investigate the use of liver moss (Dumortiera hirsute Sw. nees) as an alternative adsorbent for the removal of nickel, copper and cadmium from aqueous solution. The results showed that equilibrium contact time was 60 min and acidic pH was favourable for removal of metal ions. Higher initial metal ion concentrations led to lower removal. The data were fitted well both Langmuir and Freundlich isotherms. The monolayer adsorption capacities were 30.675, 35.971 and 53.476 mg/g for nickel, copper and cadmium, respectively. The presence of metal ions such as sodium, potassium and magnesium at concentration of 10 mM was found to have no significant effect on the removal of nickel, copper and cadmium. The removal of nickel, copper and cadmium was markedly inhibited, however, in the presence of calcium ion and heavy metal ions mixture in solutions. The kinetic data for removal processes were described by the pseudo-second-order model. The liver moss shows high potential as an economic and abundant material for the removal of metal ions from aqueous solution.

Fe3O4 nano-particles prepared by co-precipitation method using local sands as a raw material and their application for humic acid removal

Magnetic Fe3O4 nano-particles were prepared successfully from commonplace sands as a raw material. The nano-particles were synthesized by chemical co-precipitation of high purity iron separated from commonplace sands through acidic leaching. The characterization of the synthesized nano-particles was performed using X-ray diffraction, fourier transform infrared, scanning electron microscopy, transmission electron microscopy, and potential zeta. Finally, the nano-particles were used for adsorption of humic acid (HA) from aqueous solutions using batch adsorption technique. The effects of pH, adsorbent dosage, agitation time, initial HA concentration, and temperatures on HA adsorption were evaluated. The adsorption of HA onto nano-particles followed the Sips isotherm and pseudo-second order kinetics models. Thermodynamic parameters data indicated that the HA adsorption process was non-spontaneous and endothermic under the experimental conditions. The adsorption of HA from peat water (the real sample) using the nano-particles demonstrated that they were an adsorbent with great potential for the removal of HA from peat water.

Molecularly imprinted polymers (MIPs): a functional material for removal of humic acid from peat water

AbstractThe aim of this study is to investigate the use of moleculary imprinted polymers (MIPs) material as an alternative adsorbent for the adsorption of humic acid (HA) from peat water in batch mode. The MIPs were prepared with methyl methacrylate as a monomer, HA as templates, ethylene glycoldimethacrylate as a cross-linker, and dimethyl formamide as a solvent. The characteristics of MIPs were evaluated using Fourier transform infra-red spectroscopy, scanning electron microscope, and Brunauer–Emmett–Teller methods. The Langmuir, Freundlich, and Sips models were applied to describe the equilibrium isotherms using non-linear regression analysis. Pseudo-first-order, pseudo-second-order, intraparticles, and Boyd kinetic models were used to describe the kinetic data. The results showed that the equilibrium contact time was 60 min. The experimental results indicated that the percentage of sorption increases with an increase in the adsorbent dosage and temperature. The adsorption percentage decreased with inc...

Fabrication of Carbon Paste Electrode Modified with Phenol Imprinted Polyaniline as a Sensor for Phenol Analysis by Potentiometric

A phenol imprinted polymer modified electrode has been prepared by electropolymerization technique in the solution containing aniline as monomer and phenol as a template onto carbon paste electrode surface. A potentiometric method was used to evaluate the performance of the electrodes. Optimization of aniline and phenol composition and a number of polymerization cycles was investigated based on the Nernstian factor. The performance of the electrode sensor is affected by the pH of the analyte solution. Based on the potential response of three different electrodes, it is known that MIP modified electrode has better sensitivity than non-imprinted electrode or bare carbon paste electrode.

Adsorption of methyl orange from aqueous solution onto PMMA nanofiber: Kinetics study

The potential of polymethyl methacrylate (PMMA) nanofiber prepared by the electrospinning technique for the methyl orange (MO) adsorption from aqueous solution was investigated. In this study, the adsorption experiments were carried out to investigate the effect of temperatures in a batch system. From experiment it can be seen that the MO adsorption using PMMA nanofiber increased with increasing temperature. The kinetic data of MO were analyzed by pseudo-first-order and pseudo-second-order kinetic models. It was found that the amount of MO adsorbed increase with increasing temperature. Kinetics parameters data indicated that the MO adsorption onto PMMA nanofiber was found to follow both pseudo first and second-order rate equations.

Electropolymerized of aniline as a new molecularly imprinted polymer for determination of phenol: A study for phenol sensor

This paper deals with the application of polyaniline conducting polymer as a new sensor material for detection of phenol. The sensor is designed using bare carbon paste electrode (cPE), nonimprinted polymer-modified electrode (CPE/NIP) and imprinted polymer-modified electrode (CPE/MIP). These electrodes were prepared by electropolymerization of the monomer (aniline) in the presence of phenol as the template onto a carbon paste electrode. A CPE/MIP sensor which is modified with carbon paste electrode was able to detect the analyte more selectively. Several results regarding a decreasing in sensor activity were discussed. The ability of the electrodes to recognize the analyte was characterized using cyclic voltammetry (CV) in of 0.1M K3[Fe(CN)6]/0.1M K4[Fe(CN)6] acted as an electroactive specie at scan rate100 mV/s between potentials of −0.2–0.8 V by cyclic voltammetry under the optimal experimental condition.

Density Functional Study of Spin Polarization on a Carbon Material with a Hexagonal Structure Induced by Iron Atoms

We investigate the spin polarization of a non magnetic material, e.g., a carbon material made from ten C atoms forming a hexagonal structure with total spin S = 0, induced by a ferromagnetic material, e.g., two Fe atoms with a total spin S = 4. Based on the density functional theory, we calculate the total spin density of the system. Our preliminary results show that the total spin for the ten C atoms changes from S = 0 to S = 4, while the total spin of the two Fe atoms changes from S = 4 to S =0. These results seem to indicate that there is a promising possibility to induce spin polarization on a carbon material by Fe atoms.

Theoretical investigation of a benzene-vanadium multiple-decked sandwich chain on a gold surface

We investigate the formation and magnetic properties of benzene-vanadium multipledecked sandwich chain on Au(111) surface using first principles calculations based on density functional theory. We show that in the formation of the chain on the surface, each of the two hydrogen atoms of benzene bonds with only one gold atom, while the carbon and vanadium atoms do not contribute to bonding. We find that this system has no magnetic moment where two vanadium atoms are antiferromagnetically arranged, for which we suggest a superexchange interaction mechanism.