Jurnal Riset Kimia
Not a member yet
325 research outputs found
Sort by
Uji Efektivitas Ekstrak Biji Lamtoro (Leucaena leucocephala) sebagai Insektisida terhadap Kecoa Amerika (Periplaneta americana)
Get PDFResearch on the effectiveness of lamtoro seeds (Leucaena leucocephala) extract has been carried out as an insecticide against American cockroaches (Periplaneta americana). The lamtoro seeds were extracted using maceration method with ethanol solvent, and obtained ethanol extract of lamtoro seeds. Lamtoro seeds extract was made in 5 concentrations of 0%, 2%, 6%, 10% and 14%. The effectiveness of the extract was tested using spray method with 10 adult cockroaches as a testing animal with 3 times repetition and observed for 72 hours. Observations have shown the decline in American cockroaches’ activity is causing death. Mortality data were analyzed using probit analysis to determine LC50. The result of phytochemical test of lamtoro seeds extract are flavonoids, tannins and saponins. Lamtoro seeds extract was effective to kill American cockroaches, which percentage of mortality were 0%, 33%, 66%, 86% and 96% respectively at concentration 0%, 2%, 6%, 10%, and 14% with LC50 3,35%.Â
Penentuan Resistivitas Tak-Terkompensasi Cairan Ion Berbasis Imidazol dengan Metode EIS: Pengaruh Panjang Alkil dan Perbedaan Anion
Get PDFIonic liquids have interesting properties because they have several advantages compared to conventional organic solvents, such as high thermal stability, high viscosity, good solvent properties, non-flammable, and non-volatile. In electrochemistry, ionic liquids can be used as solvents without the addition of electrolytes. However, ionic liquids still have resistivity properties (uncompensated resistance), thus ohmic drop measurements are needed for a potential correction. Imidazole-based ionic liquids, which are known for their high conductivity and commonly used as a solvent, have been measured of their resistivity as a function of temperature, and type of their cations/anions. Electrochemical Impedance Spectroscopy (EIS) method was chosen to measure the resistivity of ionic liquids and Bode plot was generated for the analysis of the results. The measured resistivities of ionic liquids are in the range of 420 to 1500 ohm. It is concluded that the resistivity of the imidazole-based ionic liquid is influenced by the size of their constituent ions, the viscosity, and the resistance is decreased with increasing temperature
Pengaruh Penggunaan Fly Ash dari Berbagai Sumber terhadap Sifat Kimia dan Sifat Fisika pada Semen Tipe I (OPC)
Get PDFThe aim of this study is to utilize fly ash from various sources on chemical and physical properties of cement type I (OPC). Utilization of fly ash can improve the strengthness of the cement. It can reduce the waste of fly ash by utilization into cement process. The procedure has been carried out on cement type I (OPC) with the addition of fly ash additives from various sources with concentration variations such as 10% and 20%. Utilization of fly ash as additives substance in cement works to improve the quality of cement. The main parameter in determining the quality of cement is determined by the compressive strength. The results of the compressive strength test showed that the addition of fly ash with a concentration of 10% had a higher effect on the compressive strength than the addition of a concentration of 20%. 5 types fly ash from various sources, fly ash from PT Sinar Mas gives greater compressive strength at 28 days. the addition of fly ash additives to OPC cement mixture has chemical and physical properties which are not much different from properties of PCC cement
Validasi Metode MPM untuk Penentuan Kandungan Antioksidan dalam Sampel Herbal serta Perbandingannya dengan Metode PM, FRAP dan DPPH
Get PDFThe Modified Phenanthroline Method (MPM) has been validated for determination of antioxidant content in herb samples. Validation was done using Relative Standard Deviation (RSD) and percentage of recovery. The RSD and percentage of recovery for herb samples are 3.13% and 98.6%, respectively. Based on these values, MPM method is valid for determining antioxidant content in herb samples. T test shows no significant differences of antioxidant content using any of these methods, MPM, PM, FRAP or DPPH, at a 95% confidence level. MPM method shows a very strong correlation with PM and FRAP method. While with DPPH and TPC shows is strong
Kualitas Minyak Blend Kelapa Kopra dan Minyak Kelapa Sawit ditinjau dari Kadar Air, Kadar Asam Lemak Bebas dan Bilangan Peroksida
Get PDFThis research examined the quality of edible oil from Crude Coconut Oil (CCO) and Palm Coconut Oil (PCO) and their blends with CCO : PCO proportional was about 40:60 and 60:40, respectively. The quality of these samples was based on water proportion, free fatty acid (FFA) and peroxide value (PV) contained. This study was conducted to improve the quality of edible oil. SNI 3741-2013 was used as method of this research, which the result compared with the SNI standard for edible oil. Results of this research for water proportion in oil samples PCO, CCO, CCO (40) : PCO (60) and CCO (60):PCO (40) in order were 0.000122; 0.010905; 0.001878; 0.030996. The FFA proportions for them were 0.02; 0.01; 0.02; 0.02 and PV values were 7.10; 3.00; 6.10; 5.10, respectively. From this result, we can conclude that all samples had good quality for water proportion and FFA, except for peroxide value (PV) mark which had the higher mark compared to the SNI standard. We also concluded that CCO became the best quality of edible oil compared to others.Â
Adsorben Magnetit Terlapis Dimerkaptosilika untuk Adsorpsi Anion Logam [AuCl4]- dan [Cr2O7]-
Get PDFAdsorbent magnetite-dimercapto-silica (Fe3O4 - DMS) is a synthesis of magnetite with 2,3-dimercapto-1-propanol which has been applied to adsorb anions [AuCl4] - and [Cr2O7]-2. The adsorption process of metal anion [AuCl4]- at pH 5 with a contact time of 100 minutes was found optimum results at an adsorption capacity of 77.58 mg/g and an adsorption efficiency value of 96.975%. While the optimum conditions of metal anion [Cr2O7]-2 after the adsorption process at pH 4 with a contact time of 90 minutes was found an adsorption capacity of 85.0426 mg/g and an adsorption efficiency value of 85.0426%. The adsorption efficiency of metal anions [AuCl4]- is higher than the adsorption efficiency of metal anions [Cr2O7] -2Â
Pengaruh HCl terhadap Aktifasi Zeolit Alam Clipnotilolit-Ca Pada Penyerapan Pb(II)
Get PDFResearch about the effect of HCl on the activation of clinoptilolite-Ca natural zeolite on Pb(II) absorption has been done. The purpose of this study is to determine the capacity of zeolite clinoptilolite-Ca activation by HCl can be used as an adsorbent. For analysis of the adsorption we used AAS whereas for zeolite characterization were used XRF and XRD. The analysis parameters are the effect of HCl concentration, particle size, adsorbent mass, contact time, total solution volume, concentration of Pb(II), and PH solution. These parameters were studied to determine the optimum conditions in the adsorption process. The optimum conditions absorption of Pb(II) for the acid activation process shows that the zeolite clinoptilolite-Ca can be used as an absorbent. The adsorption results show that the value of Pb(II) capacity in the activation process with HCl of 0.2 N produces adsorption capacity of 0.0821 mg/g, for particle size 125 µm produces and adsorption capacity 0.0821 mg/g, for an adsorbent mass of 0.1 g produces an adsorption capacity of 0.5110 mg/g, for contact time of 10 minutes is 0.5662 mg/g, for a metal solution volume of 12.5 mL is 0.5493 mg/g, for the concentration of metal ion solution 40 mg/L is 2.608 mg/g, and at pH = 7 is 4.923 mg/g. The output of several parameters can be concluded that the adsorption capacity of zeolite clinoptilolite-Ca to the absorption of Pb(II) is 4.923 mg/g. Characterization of zeolite adsorbents with XRF and XRD shows that the zeolite used is zeolite clinoptilolite-Ca.  Â
Sintesis dan Karakterisasi Enkapsulat Katalis Nikel (II) pada Silika Mesopori Modifikasi
Get PDFNi(II)-BF3/MCM-41 was synthesized for heterogeneous catalyst. The boron trifluoride modified mesoporous silica BF3/MCM-41 was studied to investigate its ability as supporting agent in heterogeneous catalysis system. For this purpose, the structural directing agent remaining in as-synthesis MCM-41 removed by solvent extraction. Surface modification of mesoporous silica MCM-41 with aniline and boron trifluoride was carried out. Then, the surface of boron trifluoride modified mesoporous silica was subjected to an encapsulation with Ni(II) ions. These solid materials were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and atomic absorption spectroscopy (AAS). In the FTIR spectra of the modified silica mesoporous, the presence of vibration band >Si-O-B confirm the success of modification of support. While, the shifting of the vibration band >Si-O-Si< is considered an indication of the proof of Ni(II) species onto the modified mesoporous silica. From the SEM photograph, it can be seen that the morphology of the Ni(II)-BF3/MCM-41 tend to form aggregates of smaller particles. Based on measurement of metal content by AAS, it was known that the value of metal loading is 33%. While for the leaching test, Ni(II)-BF3/MCM-41 lost only 0.014 % of Ni metal. It indicates the stability of the interaction between the N(II) and support of the modified mesoporous silica
