Strontium is a heavy metal that is commonly found in many groundwater systems because of migration from historic nuclear waste storage sites. Its radiation effect can cause bone cancer, tumors, and leukemia. An economical and the most effective method to remove heavy metals from aqueous solutions is adsorption. In this study, we synthesized a TiO2-pillared zeolite to improve the adsorption efficiency of the zeolite. The TiO2-pillared zeolite was synthesized via the pillarization process. Adsorbent characterization was done using X-ray powder diffraction, which showed that TiO2 was successfully pillared. Fourier-transform infrared spectroscopy showed a shift in the peak at a wavenumber of 3425.70 cm −1 , which can be attributed to the addition of TiO2. A parameter study conducted using a batch experiment showed that optimal strontium adsorption took place at pH 5 and contact time of 80 min. The Freundlich adsorption isotherm fitted the experimental data well, illustrating the adsorption of strontium as being non-ideal, reversible, and multilayer adsorption that occurs on the heterogeneous surface of the TiO2-pillared zeolite. A thermodynamic study indicated that strontium adsorption on the TiO2-pillared zeolite was an endothermic process, takes place spontaneously, and is quite stable.

The lack of consumable water in urban and industrial-dense areas encourages research on clean water treatment methods. Some current treatment methods, such as precipitation, adsorption, and UV light irradiation are ineffective for water with high levels of suspended solids, organic matter, and turbidity.  Therefore, alternative approaches are required to support the availability of clean and consumable water. The membrane technology is an alternative filtration method proposed in the East Surabaya's municipal waterworks area. The membrane filtration method is quite simple and easy to operate. This study aimed to determine the performance of cellulose acetate-based porous plate membranes synthesized by phase inversion for E. coli bacteria's ultrafiltration. As a raw material, cellulose acetate is preferred because of its high hydrophilicity and good biocompatibility. Membrane synthesis was carried out through the phase inversion method with acetone solvents and non-solvent water in the coagulation bath. The positive test for E. coli bacteria was carried out through the MPN (Most Probable Number) method on the municipal waterworks water samples before and after filtering with membranes. The results showed that the synthesis of cellulose acetate membrane had good homogeneity. This result was supported by the results of ANOVA single factor statistical data analysis. Also, cellulose acetate membrane had good permeability and flux performance as ultrafiltration of E. coli bacteria with a flux of 37.25 L/m2.hour.bar at a sufficient pressure of 5 bar. Test results for the presence of E. coli bacteria in PDAM water samples using the MPN method gave an initial indication that the water sample after filtration with cellulose acetate membrane was negative. Keywords: membrane, cellulose acetate, permeability, water fluxABSTRAKMinimnya air bersih yang layak konsumsi di daerah perkotaan dan padat industri mendorong penelitian tentang metode pengolahan air bersih. Kurangnya efektivitas metode pengolahan sebelumnya seperti pengendapan, adsorbsi, dan penyinaran dengan sinar UV untuk air dengan kadar suspended solids, zat organik, dan kekeruhan yang tinggi, diperlukan metode alternatif untuk mendukung ketersediaan air bersih layak konsumsi. Metode filtrasi alternatif yang ditawarkan di PDAM di kawasan Surabaya Timur. Metode filtrasi dengan membran sangat sederhana dan mudah dalam operasionalnya. Penelitian ini bertujuan untuk mengetahui kinerja membran plat berpori berbasis selulosa asetat yang disintesis secara inversi fasa untuk ultrafiltrasi bakteri E.coli. Selulosa asetat dipilih sebagai bahan baku membran karena selulosa asetat merupakan bahan polimer yang memiliki hidrofilitas tinggi dan biokompatibilitas yang baik. Sintesis membran dilakukan melalui metode inversi fasa dengan pelarut aseton dan nonpelarut air dalam bak koagulasi. Uji positif bakteri E.coli dilakukan melalui metode MPN (Most Probable Number) pada sampel air PDAM sebelum dan sesudah difiltrasi dengan membran. Hasil penelitian menunjukkan bahwa sintesis membran selulosa asetat memiliki homogenitas baik yang ditunjukkan oleh hasil analisis data statistika ANOVA single factor. Selain itu, membran selulosa asetat memiliki kinerja permeabilitas dan fluks yang baik sebagai ultrafiltrasi bakteri E.coli dengan ketercapaian fluks sebesar 37,25 L/m2.jam.bar pada tekanan efektif sebesar 5 bar. Hasil uji keberadaan bakteri E.coli pada sampel air PDAM dengan metode MPN memberikan indikasi awal bahwa sampel air setelah filtrasi dengan membran selulosa asetat adalah negatif.Kata kunci: membran, selulosa asetat, permeabilitas, fluks air

Low dose gamma film dosimeter based on chitosan and starch bio-polymer with methyl orange dyes has been synthesized and characterized. The aim of this research was to synthesis radiochromic film dosimeter used biopolymer material such as chitosan and starch with methyl orange dyes as the color indicator and also to investigate the effect of gamma irradiation on film dosimeter response. The film dosimeter was prepared by mixing chitosan and starch at gelatinization temperature then added with methyl orange dyes. Biopolymer solution then casting on the flat glass to produce a thin film with uniform thickness, after that film dosimeter was irradiated at 1, 3, 5, and 9 kGy. To analyze the quantitative response of irradiation, the film dosimeter was characterized by UV-Visible. The result shows that the film dosimeter has changed its color as a response to the irradiation. The higher the dose of gamma irradiation, the higher the net absorbance of it. This research showed that bio-polymer based chitosan and starch is material that has the potential for low dose gamma dosimeter.

The Effect of Gamma Iradiation Dosage Variation on The Separation of Coconut Coir Lignocellulose Biomass ComponentsAbstractIndonesia has the potential for lignocellulosic biomass in the form of coconut coir, which is very abundant. The components of coconut coir are lignocellulosic biomass, which consists of cellulose, hemicellulose, and lignin and can be separated from one another. This study was conducted to determine the effect of variations in the dose of gamma-ray irradiation on the structure of each component so that it was expected that the utilization of coconut coir lignocellulosic biomass could be more comprehensive. The separation was carried out using wet irradiation with a 5% H2O2 solution as the initiator, where 15 grams of coco coir sample was dissolved in 60 ml of 5% H2O2 solution. Gamma irradiation dose variations were 0 kGy, 50 kGy, 100 kGy, 150 kGy, and 200 kGy. Based on the research, the optimal dose to obtain glucose was obtained at an irradiated dose of 100 kGy with a glucose level of 5.09 mg. The optimal gamma irradiation dose for lignin separation is 50 kGy with a lignin separation percentage of 34.95%. Based on the FTIR analysis, it can be seen that as a result of the chemical bond resulting from the separation, there is a decrease in the effect of the gamma IR radiation. This study showed that the separation of lignocellulosic coconut coir biomass using gamma irradiation could produce higher levels of glucose and lignin separation and affect the chemical structure of cellulosic biomass