Fe3O4 (magnetite) nanoparticles were synthesized by chemical co-precipitation method. The structure, morphology and magnetic properties of as-prepared were characterized by X Ray Diffraction (XRD), Scanning Electron Microscope-Energy Dispersive X Ray Spectrometry (SEM-EDS), Transmission Electron Microscope (TEM) and Vibrating Sample Magnetometer (VSM). The result of XRD characterization was indicated Fe3O4 as the product. SEM and TEM image of the Fe3O4 showed nanoparticles Fe3O4 have the mean diameter 5-20 nm. The EDS spectra showed strong peaks of Fe and O. Magnetic characteristic of Fe3O4 nanoparticles was indicated super paramagnetic properties. The saturation magnetic was 89.46 emu g-1. Therefore, the nanoparticles Fe3O4 is suitable to remove dye in the water by a simple magnetic separation process. The optimum adsorption occurred at initial concentration of procion dye 100 mg L-1, pH solution 6, dosage of Fe3O4 0.8 g L-1 and contact time 30 minutes under room temperature with color removal 24.40 % and adsorption capacity was 30.503 mg g-1

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The synthesis chitosan-methylene bridge-Schiff base of 4,4-diaminodiphenyl ether-vanillin using casting method has been done. The aims of this research were modification chitosan with Schiff base of 4,4-diaminodiphenyl ether-vanillin, formaldehyde and its characterization using FTIR spectroscopy, SEM analysis, 1H-NMR and X-Ray Diffraction analysis. The first step was a synthesis of modified chitosan between chitosan and Schiff base of 4,4-diaminodiphenyl ether-vanillin. The second step was chitosan modified Schiff base of 4,4-diaminodiphenyl ether-vanillin then reacted with formaldehyde through casting method. The result showed that chitosan can be modified with Schiff base of 4,4-diaminodiphenyl ether-vanillin and formaldehyde and this modified chitosan can be linked by methylene bridge (-NH-CH2-NH-) and had azomethine group (-C=N-). The functional group of –C=N in modified chitosan before and after adding formaldehyde appeared at a constant wavenumber of 1597 cm-1. The functional group C-N in methylene bridge detected at 1388 and 1496 cm-1. The chitosan-Schiff base of 4,4-diaminodiphenyl ether-vanillin and Chitosan-methylene bridge-Schiff base of 4,4-diaminodiphenyl ether-vanillin had index crystalline (%)16.04 and 25.76, respectively. The chemical sift of signal proton azomethine group (-C=N-) in modified chitosan detected at 8.44–8.48 and 9.77 ppm. Proton from methylene bridge in modified chitosan appeared at 4.97–4.99 and 3.75 ppm. Surface morphology chitosan-methylene bridge-Schiff base of 4,4-diaminodiphenylether-vanillin had dense surfaces, mostly uniform and regular in shape.

This study successfully synthesized a core-shell-shell in the form of CoFe 2 O 4 -SiO 2 -TiO 2 catalyst magnetic and recyclable. The catalyst was employed for the photocatalytic degradation of methyl orange (MO) dye. Subsequently, the catalyst was subjected to XRD, FTIR, SEM-EDS, VSM, as well as UV-DRS characterizations. The photocatalytic degradation was studied as a function of the solution pH, MO concentration, and irradiation time, while the kinetics of photocatalytic degradation and the catalyst reusability were also evaluated. On the basis of the XRD, FTIR, and SEM-EDS characterizations, the CoFe 2 O 4 coating was successfully carried out using SiO 2 and TiO 2 . CoFe 2 O 4 -SiO 2 -TiO 2 was discovered to possess magnetic properties with a saturation magnetization of 17.59 emu/g and a bandgap value of 2.4 eV. The photocatalytic degradation of MO followed the Langmuir-Hishelwood model. The optimum degradation was obtained at the MO concentration of 25 mg/L, solution pH of 4, catalyst dose of 0.05 g/L, irradiation time of 160 minutes, MO removal efficiency achieved 93.46%. The regeneration study showed CoFe 2 O 4 -SiO 2 -TiO 2 after 5 cycles were able to catalyze the photocatalytic degradation with an MO removal efficiency of 89.96%.

Nano-hydroxyapatite was synthesized by coprecipitation method and tested its antibacterial properties. Nano-hydroxyapatite was synthesized using CaO precursors from snakehead (Channa striata) fish bones and (NH4)2HPO4. The synthesis was carried out with temperature variations of 30, 60, 80, and 100 °C. Antibacterial activity was determined using two types of bacteria, namely gram-positive and gram-negative. The XRD spectra show that the highest peak is hydroxyapatite synthesized at a temperature of 100 °C. Hydroxyapatite produced from various synthesis temperatures has the size of nanoparticles in the range 37.32-49.27 nm. The nano-hydroxyapatite functional groups are characterized using FTIR, the analysis indicate the presence of OH, CO32‒ and PO43‒. The molar ratio Ca/P is obtained of 1.71 approaching theoretical hydroxyapatite of 1.67. The resulted nano-hydroxyapatite has significant antibacterial properties to Escherichia coli and Staphylococcus aureus.

The study on cellulose modification with acetic acid to cellulose-acetate has been carried out. Cellulose is extracted from the kepok banana peel (Musa paradisiaca L.). Modified cellulose acetate was characterized by FTIR spectroscopy and SEM-EDS. Cellulose acetate to removal of methylene blue with adsorption parameter include initial concentration (10, 20, 30, 40, 50, 60, 70, 80, 90 and 100 mg/L), pH solution (3, 4, 5, 6, 7, and 8) and contact time (15, 30, 45, 60, 75, and 90 minutes). The peak of FTIR cellulose acetate obtained by functional groups -OH, C-H, C=O, and C-O esters. The morphology of cellulose-acetate has a more homogeneous than cellulose. Adsorption of cellulose-acetate on methylene blue optimum at an initial concentration of 90 mg/L, pH of solution 6, and contact time of 30 minutes. The adsorption kinetics corresponds to pseudo-second order and adsorption equilibrium corresponds to Langmuir isotherms with adsorption capacity of 42.107 mg/g.

Batanghari River is one of the fishing locations in Jambi Province, Indonesia. One of the commercial freshwater fish in this river is silver shark minnow Osteochilus vittatus. Presently, there was no study on the bioecology of this species in Batanghari river. Therefore, the aims of this research were to analyze the growth pattern, reproduction, and food habits of silver shark minnow in Batanghari River, Indonesia. Data were collected in February, April, June, September, and October 2018. The samples were preserved with alcohol 70%. The length-weight relationships were analyzed using the linear allometric model, gonad maturity was observed by morphologically, and fecundity was calculated by the gravimetric method. The results showed that this fish had an isometric growth pattern. The fish fed on phytoplankton and indicated as herbivorous plankton feeder. Bacillariophyceae and Chlorophyceae were predominant food items. The fish spawn around the year partially with fecundity between 2,726 - 19,202 eggs. The gonad maturity index ranges from 5.38% to 11.44%, and the egg diameter ranged from 0.40 to 1.27 mm.

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