Mohammad Khotib
Department Of Chemistry, Faculty Of Mathematic And Natural Sciences, Bogor Agricultural University, Darmaga Campus, Fapet Building W2 Lt 4-5, Agatis Street, Bogor 16680; Integrated Laboratory, Bogor Agricultural University, Baranangsiang Campus, Paja

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Journal : Indonesian Journal of Chemistry

Thermodynamic and Kinetic Study of Zinc bis-(Dipalmithyl Dithiophosphate) Activity as Anti-Corrosion Additive-Fatty Acid Based Through Potentiodynamic Polarization Technique Komar Sutriah; Zainal Alim Mas’ud; Mohammad Khotib; Denar Zuliandanu
Indonesian Journal of Chemistry Vol 16, No 2 (2016)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (493.913 KB) | DOI: 10.22146/ijc.21166

Abstract

Zinc bis-(dipalmithyl dithiophosphate) (ZDTP16) is one product variant of zinc dialkyl dithiophosphate (ZDTP)-fatty acid based having function as corrosion inhibitor. By using 3% of effective dose for the application, its effectiveness of ZDTP16 corrosion inhibition will achieve 97% and it will be able to decrease Cu metal corrosion rate from 0.152 to 0.004 mm per year. Thermodynamic and kinetic parameter verification indicates the decreasing of spontaneity and corrosion rate by existence of ZDTP16 inhibitor. Gibbs free energy transition corrosion of Cu metal in electrolyte medium is measured in corrosion simulator increased from +85.22 to +91.77 kJ mol-1, while its activation energy increased from +16.66 to +33.68 kJ mol-1. Morphology observation of Cu metal substrate surface using SEM-EDX shows that the adsorption of ZDTP16 at substrate surface is able to protect surface from corrosion indicated by the existence of Zn, P, S, and C constituents representing composer atoms of ZDTP16, and the decreasing of Cl- corrosive constituent at substrate surface.
Performance of Zinc-Difattyalkyldithyocarbamate as Anti-Friction/Anti-Wear Lubricant Additives Komar Sutriah; Zainal Alim Mas’ud; Tun Tedja Irawadi; Mohammad Khotib
Indonesian Journal of Chemistry Vol 14, No 1 (2014)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (592.03 KB) | DOI: 10.22146/ijc.21271

Abstract

Dithyocarbamate is an organosulphur compound that has long been known and widely applied in various fields, including in agriculture and industry. Several variants of synthesized vegetable oil-based Zinc-difattyalkyldithyocarbamate were tested its anti-friction/anti-wear performance on four ball machine using the method of ASTM-D2783. Anti-friction/anti-wear test to six of additive variants of Zinc-difattyalkyldithyocarbamate at doses of 1.2% indicated that all variants of the product has welding point value higher than the lube base oil lubricant HVI 60, and from US Steel 136 standard for Hydraulic lubricants, but only two additive variants of Zinc-bis(lauryl palmityl)dithyocarbamate and Zinc-bis(lauryl oleyl)dithyocarbamate which has a larger load wear index value than the standard, and meet the criteria as an additive extreme pressure according to US steel 136 standard. Zinc-bis(lauryl palmityl)dithyocarbamate is an additive variant with the best performance, meet bi-functional lubricant additives criteria, as anti-friction/anti-wear and antioxidant additive.
Synthesis of Cassava Waste Pulp-Acrylamide Super Absorbent: Effect of Initiator and Cross-Linker Concentration Zainal Alim Mas’ud; Mohammad Khotib; Nurmutia Sari; Anwar Nur
Indonesian Journal of Chemistry Vol 13, No 1 (2013)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (2601.851 KB) | DOI: 10.22146/ijc.21328

Abstract

Cassava waste pulp (CWP) contains high carbohydrates that can be modified into super absorbent polymer (SAP) through grafting and cross-linking copolymerization. Acrylamide (AM) was grafted onto CWP with ammonium persulfate (APS) as the initiator and N,N'-methylene-bis-acrylamide (MBA) as the cross-linker under atmospheric nitrogen. The effect of APS and MBA concentrations on water absorption capacity of saponified SAP was studied, while the evaluation of grafting ratio (GR) and grafting efficiency (GRE) was conducted on unsaponified SAP. The grafting success was indicated by the occurrence of IR peaks at wave numbers of 573, 765, 858, and 1667 cm-1. In the saponified SAP, the very intense characteristic band at 1562 cm-1 is due to C=O asymmetric stretching in the carboxylate anion. Saponification increases significantly water absorption capacity compared to that of unsaponified SAP (from 39.79 g/g to 578.23 g/g). The highest water absorption capacity is reached at 0.74% APS and 0.09% MBA. The percentage of GRE and GR tends to increase with increasing APS concentration until reaching the highest value and then decreases. Effect of MBA concentration on water absorption capacity, GR, and on GRE is similar to the effect of initiator concentration on GR and GRE.
Synthesis of TiO2/Carbon Nanoparticle (C-dot) Composites as Active Catalysts for Photodegradation of Persistent Organic Pollutant Dedri Syafei; Sri Sugiarti; Noviyan Darmawan; Mohammad Khotib
Indonesian Journal of Chemistry Vol 17, No 1 (2017)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (332 KB) | DOI: 10.22146/ijc.23615

Abstract

TiO2/C-dot composites were synthesised by sol-gel method and  investigated as catalysts for photocatalytic degradation of persistent organic pollutants (perchloroethylene, PCE). The composites photoluminescence properties was shown by visual analysis and the synthesis product was characterized by XRD, FTIR, fluorescence spectrophotometer, and UV-Vis spectrophotometer. Degradation of PCE 0.1% (v/v) in the aqueous phase was investigated under sunlight irradiation for 2 h. Photodegrade efficiency of PCE was determined by GC. Composites of TiO2/C-dot 2.5% (w/w) was succesfully to degrade PCE under sunlight irradiation and its photodegrade efficiency was up to 89.45%.
Growth, Electronic Structure, and Electrochemical Properties of Cubic BaTiO3 Synthesized by Low-Pressure Hydrothermal-Assisted Sintering Mohammad Khotib; Bambang Soegijono; Zainal Alim Mas'ud; Gina Libria Nadjamoeddin
Indonesian Journal of Chemistry Vol 22, No 1 (2022)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.68978

Abstract

Cubic BaTiO3 was synthesized through low-pressure hydrothermal-assisted sintering using Ba(OH)2 and TiO2 as precursors with a mol ratio of Ba:Ti = 1.4:1. The single phase of cubic BaTiO3 was produced at a sintering temperature of 800 °C for 2, 4, 8, and 12 h. The absence of diffraction peak splitting at 2q of 45° was indicated cubic BaTiO3. The crystallite size of BaTiO3 ranged from 80–200 nm, and its size increased with increasing temperatures and sintering times. The micro-strain of the BaTiO3 crystal lattice had a range between 0.27 and 0.68%. The minimum bandgap on the indirect bandgap was about 1.75 eV from point M to Γ, while the direct bandgap was about 1.95 eV from Γ to Γ. Ti–O's interaction had a covalent character, while that of Ba–O had an ionic character based on the density of state (DOS) calculation. The characteristics of the BaTiO3 voltammogram show an irreversible redox mechanism with a more observable reduction peak in Ti4+/Ti3+. Higher current density at over potential indicated greater BaTiO3 capabilities in Oxygen Evolution Reaction (OER)-Oxygen Reduction Reaction (ORR) electrocatalysis. For that, purified cubic BaTiO3 offers potential application as an electrode for batteries, water splitting systems, and regenerative fuel cells.