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Electrocatalytic parameters of a Pt/C standard and a sample of terbium(III) monoporphyrinato were investigated in different solutions. N electron transfer, Tafel slope, Eonset, and overpotential of the catalyst of Pt/C in different solutions were calculated and analyzed using a rotating ring disk electrode (RRDE) in 0.5 M H2SO4, 0.1 M HClO4 and 0.1 M NaOH. In the RRDE measurements, a bipotentiostat at a potential range of 1.03 to 0.05 V vs RHE (Ering = 1.2 V vs RHE) with a scan rate of 5 mV/s and rotation rates of 200, 400, 900, 1600 and 2500 rpm was used. Hereafter, the test of terbium(III) monoporphyrinato compound formulated in [Tb(TPP)(cyclen)]Cl (TPP = 5,10,15,20-tetraphenylporphyrinato; cyclen = 1,4,7,10-tetraazacyclododecane) as a candidate material for ORR electrocatalyst was also done. The results showed that the measurement of Pt/C standards was satisfactory according to the literature for all parameters with the n electron transfer close to 4 in all electrolytes media. [Tb(TPP)(cyclen)]Cl had an n electron transfer value of 2.38, suggesting that the [Tb(TPP)(cyclen)]Cl compound has less potential for ORR catalysts.

This paper reports the synthesis of Fe(II)/Co(II) fused triphenyl porphyrin dimers as candidate of hybrid organic metal electrocatalyst. The synthesis was conducted in five-step reactions using the starting materials pyrrole and benzaldehyde. The fuse oxidative reaction was done via free-base form of triphenyl porphyrin to omit metal insertions/removals of intermediate products. This strategy is very beneficial for the synthesis of metal fused triphenyl porphyrin that needs less reactions where phenyliodine(III) bis(trifluoroacetate) (PIFA) was successfully deployed in the oxidative reaction of two free-base triphenyl porphyrins. Here, the comparisons of NMR spectra were presented to see the changes of the starting material to the product. Initial electrochemical tests showed that reduction current of planar structure of Fe/Co fused triphenyl porphyrin dimer was on the potential range at -1.10 V to 0.45 V vs Au. Fe-fused triphenyl porphyrin dimer with 7.58 × 10–4 A (-1.05 V) showed slightly better performance than Co-fused triphenyl porphyrin dimer with 5.67 × 10–4 A (-0.97 V).

The aims of this research is to synthesize Pb(II) imprinted polymers with carboxymethyl chitosan (CMC) as polymers and bisphenol A diglycidyl ether (BADGE) as cross-linker (Pb-IIP). Chitosan (CTS), non imprinted polymer (NIP) and Pb-IIP were characterized using infrared (IR) spectroscopy, X-ray diffraction (XRD), surface area analyzer (SAA), scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) spectroscopy. The result showed that the adsorption was optimum at pH 5 and contact time of 250 min. Adsorption of Pb(II) ion with all of adsorbents followed pseudo-second order kinetic equation. Adsorption of Pb(II) ion on CTS followed Freundlich isotherm while that on NIP and Pb-IIP followed the Langmuir adsorption isotherm. The adsorbent of Pb-IIP give higher capacity than the NIP and CTS. Adsorption capacity of Pb-IIP, NIP and CTS were 167.1, 128.9 and 76.1 mg/g, respectively. NIP gave higher adsorption selectivity for Pb(II)/Ni(II) and Pb(II)/Cu(II), whereas Pb-IIP showed higher adsorption selectivity for Pb(II)/Cd(II).The hydrogen bonding dominated interaction between Pb(II) ion on NIP and Pb-IIP.

The aims of this research is to synthesize a chitosan derivative insoluble in acidic aqueous medium and that has high adsorption capacity for Pb(II) ions by cross-linking and grafting. Cross-linking and grafting were done using ethylene glycol diglycidyl ether (EGDE) and chloroacetic acid, respectively. The modified chitosan was characterized using FTIR spectrophotometer, XRD and TG-DTA. Chitosan and Chit-EGDE-Acetate was applied as adsorbent of Pb(II) ions in a batch system. The concentration of Pb(II) in adsorption medium was quantified using AAS. The result showed that the adsorption was optimum at pH 5, contact time of 200 min for chitosan and 300 min for Chit-EGDE-Acetate. Adsorption of Pb(II) ions on both adsorbents followed pseudo second order kinetic equation. Adsorption of Pb(II) ions on chitosan followed Freundlich isotherm while that on Chit-EGDE-Acetate followed the Langmuir adsorption isotherm. The adsorption capacity of Chit-EGDE-Acetate for Pb(II) ions was 200.0 mg L-1 while that for chitosan was 166.7 mg L-1. Interaction type of Pb(II) ions on adsorbent was determined by sequential desorption.

Complex of cobalt(II) with sulfisoxazole (slfs) has been synthesized in 1 : 4 mole ratio of metal to ligands in methanol, the complex formula is [Co(slfs)3(H2O)3]SO4.nH2O. The electric conductivity of the complex in methanol correspond to 1:1 electrolyte. The thermal analysis indicates that complex contain some hydrates. Magnetic Susceptibility measurements show that the complex is paramagnetic with µeff = 4,60(9) BM. Infra red spectra indicates that the primary N-H group coordinated to the center ion, it is signed by a shift of primary N-H group absorption. UV-Vis spectrum appears one peak at λ= 515,5 nm (19.342 cm-1) due to transition peak of 4T1g (F) → 4T2g (P) (ν3) overlay to transition peak of 4T1g(F) → 4A2g(F) (ν2). The value of 10 Dq (Δo) that corresponds to transition 4T1g → 4T2g (n1) is 95,29 kJ.mol-1. Cyclic voltammograms have revealed quasi reversible. The complex probably is octahedral. Keywords: cobalt(II), sulfisoxazole, complex, paramagnetic, octahedral

The objective of this research is to study wheather the emulsion system of water/SDS (Sodium Dodecyl Sulphate)/ethanol/n-hexane can be transformed from S1 (hydrocarbon in water) type to S2 (water in hydrocarbon). CdS can be synthesized in the transformed product of microemulsion medium. The emulsion type transformation from S1 to S2 was conducted by adding n-hexane increment of 5 mL as hydrocarbon phase and stirring at 300 rpm for 2 minutes. The inversion point was defined from the measurement of emulsion conductivity and was supported by data of the droplet view under optical microscope. CdS was synthesized from reaction of Cd(NO3)2.4H2O with Na2S in phase transformed microemulsion medium. CdS cluster size was obtained from its UV-Vis spectrum and was characterized using X-ray diffraction to analyse the crystallinity and crystal system, then the influence of the variation of SDS amount to the CdS cluster size and its UV-Vis spectrum was observed.The result of this research shows that the system of n-hexane/SDS/water emulsion can be transformed from S1 to S2 type. The SDS amount in the microemulsion has influence the CdS cluster size. The larger amount of SDS added, the smaller of CdS cluster size was obtained. XRD data indicated that CdS cluster has been obtained with 40.613 % of purity. Keywords: emulsion system, nanoparticle semiconductor, CdS, sodium dodecyl sulphate