Pada penelitian ini biji durian digunakan sebagai sumber pati dalam pembuatan plastik biodegradable. Penelitian ini bertujuan untuk mengetahui pengaruh jenis dan jumlah filler terhadap sifat biodegradable, sifat mekanik dan sifat water absorbtion pada plastik biodegradable berbasis pati biji buah durian. Plasticizer yang digunakan dalam penelitian ini adalah sorbitol  40%, sedangkan filler yang digunakan adalah Kalsium silikat (Ca2SiO4) dan Kalsium karbonat (CaCO3) dengan variable konsentrasi 2%, 4%, 6%, dan 8%. Dari hasil penelitian, diperoleh % yield dari pati biji buah durian sebesar 34,57%. Hasil dari plastik biodegradable terbaik dengan karakteristik transparan, tidak ada gelembung, lentur serta permukaan yang halus diperoleh pada variabel penambahan filler kalsium karbonat 4%. Hasil uji bio-degradasi paling mendekati standard ASTM D6400 diperoleh pada variabel kalsium karbonat 2%. Pada Uji water absorption hasil terbaik dicapai pada variabel kalsium silikat 8%. Uji tarik hasil terbaik diperoleh pada variabel kalsium silikat 6%.In this study, durian seeds were used as a source of starch in making biodegradable plastics. This study aims to determine the effect of the type and amount of filler on biodegradable properties, mechanical properties, and water absorption properties of biodegradable plastics based on durian fruit starch. The plasticizer used in this study was sorbitol 40%, while the filler used was Calcium silicate (Ca2SiO4) and Calcium carbonate (CaCO3) with variable concentrations of 2%, 4%, 6%, and 8%.. From the research results, the% yield of durian seed starch was 34.57%. The results of the best biodegradable plastic with the characteristics of transparent, no bubbles, flexible and smooth surface were obtained with the addition of 4% calcium carbonate filler variables. The bio-degradation test results closest to the ASTM D6400 standard were obtained in the 2% calcium carbonate variable. In the water absorption test, the best results were achieved at the 8% calcium silicate variable. The best tensile test results were obtained in the 6% calcium silicate variable.

The limestones was abundant in Tuban, East Java and have high calcium mineral content. Nevertheless, in the economic value, limestone have low price. Aim the research is prepare Precipitated Calcium Carbonate (PCC) by caustic soda method. In this method, calcium was dissolved in HNO 3 with different concentration (2, 4,6, 8 M). The Filtrate obtained then was added by Na 2 CO 3 1 M to get PCC. As the results, The white PCC obtained with the highest rendement is 64,7% when added HNO 3 6M. Analysis of functional group by FTIR show that there were strong absorption in the 844,76; 912,27 dan 1411,40 cm -1 that indicated carbonate group. Analysis of Cristallinity by XRD show that there were the peak characteristic of 2 on 29,50˚; 36,07˚ dan 39,50˚that representative calcite structure. SEM -EDX Analysis show that PCC have a mixing structure of calcite and vaterite.

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This research, the caffeine extract of arabica coffee beans, cacao beans, and black tea leaves will be tested as a corrosion inhibitor on aluminium in an acidic environment and in biodiesel containing acid. This condition resembles the metabolism of microorganisms in biodiesel which produces H2SO4 as one of the causes of corrosion. Arabica coffee, cacao beans and black tea are natural organic ingredients containing caffeine which can inhibit corrosion. In the maceration process used a variable ratio of 70% ethanol solvent with organic matter, namely 225 grams of organic matter with 450 grams of ethanol and 150 grams of organic matter with 450 grams of ethanol. Concentration of caffeine extract from arabika coffee, cacao beans, and black tea leaves was obtained based on HPLC analysis at an effluent rate of 0.8 mL/min. The corrosion inhibition efficiency test on aluminium was observed at 0, 1, 4, 7 and 10 days of immersion. The previously used aluminium has been corroded with 12% H2SO4. The corrosion inhibition efficiency test on aluminium was observed at 0, 1, 4, 7 and 10 days of immersion. The best inhibitor results on aluminium soaked in biosolar containing 12% H2SO4 is tea 1.234,313 ppm with a corrosion rate of 1.6x10-4 g/cm2 day on day 1 to 2.5x10-4 g/ cm2 day on day 10 with an inhibition efficiency of 99%. While the aluminium soaked in H2SO4 12% is tea containing caffeine of 684.373 ppm with a corrosion rate of 1.3 x10-4 g/ cm2 day on day 1 to 3.3x10-4 g/ cm2 day on day 10 with an inhibition efficiency of 64%. The longer the immersion time of aluminium in H2SO4 media with the addition of organic inhibitors, the lower the corrosion rate value because the inhibitors form a layer that protects the aluminium.

Cadmium (Cd) metal is a heavy metal that can cause environmental pollution if its levels are above the environmental quality standard value. Generally, industrial wastes such as paper industry waste contain heavy metal Cd with levels reaching 0.026 ppm. Meanwhile, the quality standard for Cd metal in the environment is 0.005 ppm. For this reason, it is necessary to process it to reduce the levels of Cd metal in the waste before being discharged into the environment. One way that can be used to reduce the levels of Cd metal is by adsorption method using Cypraea moneta clamshells containing chitin. This study used variations in the particle size of the shellfish adsorbent of 6 and 12 mesh. In addition, the ratio of the amount of adsorbate and adsorbent (mg:mg) is 1 : 0.5x106; 1 : 1x106; and 1 : 1.5x106. Based on the results obtained, it showed that the use of shellfish as an adsorbent was able to reduce Cd metal content up to 89%.