[en] Highlights: • A series of bimetallic organic framework was prepared via green synthesis method. • Adsorption capacity of Cu-Fe-BTC for MB was ~ 6 times better than CuBTC. • Presence of iron disturbed the lattice structure, enhancing adsorption. • Pore size greater than 1.7 times the width of MB, is important for adsorption. The incorporation of different percentages of Fe²⁺ into copper benzene-1,3,5-tricarboxylate (CuBTC) was successfully carried out at room-temperature synthesis with water as the only solvent. The XRD and XPS analysis shows that the Fe²⁺ were substituted into the paddlewheel structure. The incorporation of 18% Fe²⁺ into CuBTC can increase the surface area and porosity of the framework. The BET surface area of Cu₈₂Fe₁₈BTC (1240 m²/g) was significantly higher than CuBTC (708 m²/g). Further increase in the Fe²⁺ percentage will reduce the surface area of the compound. The presence of Fe²⁺ in the framework successfully disturbs the pore formation and widens the pore size on the surface of these compounds. This as well as the pH_pzc, which is related to the surface acidity of the resulting bimetallic organic framework (BMOF), play an important role in the adsorption process. Cu₅₃Fe₄₇BTC with an adsorption capacity of 94.42 mg/g shows approximately 6 times greater adsorption capacity against MB compared to CuBTC. This shows that by utilizing a different ratio of Cu and a second metal, it is possible to effectively design the surface morphology of BMOF for specific applications.

[en] The ¹⁴C natural isotope has been used to monitored exploitation effects within a 10 year interval between 1995 to 2005 in Bontang groundwater basing east Borneo- Indonesia. Exploitation of the groundwater of Bontang basin has occurred since 1981 and at the present the groundwater abstraction for Bontang basin is about 59,000 m³/day to fulfill the necessity of liquid natural gas and fertilizer industries from more than 20 wells. Isotope investigation of the groundwater Bontang basin have been done through water sources sampling like rivers, cold spring deep wells sea water and rain water in 1995 and 2005. The ¹⁸O and D isotope data show that deep groundwater originates from local rain water that infiltrates through the slope of mount Lobang Batik. Along the hilly slope zone, it is layered by the sedimentary Kampung Baru Formation. There is no indication that the Mahakam river water infiltrates and sea water intrusion to the deep groundwater. The ¹⁴C of isotope data from deep wells show that the average age of 4 wells with distance 2-3 km located from the outcrop of Kampung Baru in 1995 is about 2300 a. There is a decrease of groundwater age since exploitation to around 500 a. Decreasing of groundwater age is possible due to mixing with recent recharge through the Kampung Baru formation. (author)

[en] In response to Jambeck’s claim on Indonesian plastic marine debris, some academicians, scientists, as well as associations such as The Indonesian Olefin and Plastic Industry Association (INAPLAS), Indonesian Plastic Recycle Association (ADUPI), and Indonesian Plastic Recycle Industry Association (APDUPI) conducted a deeper plastic balance examination to clarify and enlight the Indonesian plastic marine debris amount. This study continued the previous work, which employed the river survey method to conduct a more accurate calculation in the actual condition. From the river survey results, Indonesian plastic marine debris amount is about 0.038 MT/y and it will reduce to 0.004 MT/y if the trash trap is strictly-applied. This result is not much different compare to the seashore approach but again also clarifies that Indonesia is not the second-largest contributor country for plastic marine debris. Moreover, asides from conserving the marine and river environments, installing a trash trap on the river could increase local people’s income at once. (paper)

[en] MASARO technology presents a solution in solving the waste problem through an organic waste processing unit, known as IPPO (Organic Fertilizer and Feed Industry). The Masaro system characterises solid waste into five catagories including organic waste, low value plastic waste, incenerated waste, recycled waste, and hazardous waste. The organic waste will be separated into an organic fast-decaying waste to produce POCI (Special Liquid Organic Fertilizer) and KOCI (Special Liquid Organic Concentrate), and an organic slow-decaying waste to produce a compost. POCI is used as an organic fertilizer and its farming produces a higher production number, higher quality product, faster production rate while its production cost is lower. KOCI and compost is applied in the farm industry where the organic waste with low economic value is used as a raw material to produce new materials with higher economic value. These products can produce an environmentally friendly system and reflect the circular economy principle application. The organic waste is used as raw material for IPPO and its products form a circular economy through aplication in the farm industry that create lower cost production and sustainable development. (paper)

[en] A clear and accurate plastic marine debris amount to clarify Indonesian marine debris issues still does not exist. Only Jambeck’s study estimated that millions of tonnes of plastic enter the Indonesian ocean every year, but the result is often disputed. This study, hence, was conducted to calculate the Indonesian plastic marine debris amount using Indonesian plastic national balance (IPNB) and seashore approach. The study was based on Indonesia’s 2019 data of plastic production, plastic raw material and finished-product balance, plastic recycling industry, plastic consumption, and plastic distribution. Indonesian plastic industries have a total capacity of 2.66 MT/y, production of 2.31 MT/y, import of 1.67 MT/y, and recycle of 1.655 MT/y. The results from Indonesian plastic national balance (IPNB) imply that after-used plastic of 5.755 MT/y is categorized into material still-consumed, material recycled, and plastic waste. About 90% of the plastic waste is managed which further recycled (0.654 MT/y) and ended up in the landfill (0.868 MT/y), while the rest (about 10%) is mismanaged and become marine debris (0.17 MT/y). For the results from the seashore approach, after-used plastic is burned and buried (3.228 MT/y), recycled (1.655 MT/y), ended up in the landfill (0.868 MT/y), flowed to the river (0.009 MT/y), picked up in the river (0.005 MT/y), and the rest become marine debris (0.004 MT/y). Both results differ from Jambeck’s calculation (0.48-1.29 MT/y) and therefore, clarify that Indonesia is not the second-largest contributor country for plastic marine debris. (paper)

[en] Sibayak is located in a young volcanic area of North Sumatra, Indonesia. The surface manifestations such as acid springs, fumaroles and acid alterations indicate that Sibayak geothermal field is probably associated with the volcanic system. The aims of this study are to define the origin of the geothermal fluids, reservoir temperature and interactions between the volcanic system and the geothermal reservoir. Chemical composition, stable isotopes ¹⁸O_H2O, ¹⁸O_SO4, D_H2O, ³⁴S_H2S, and ³⁴S_SO4 of water and gas samples from the geothermal surface manifestations and exploration wells are analyzed. δ¹⁸O and δD values show that the reservoir fluids of Sibayak geothermal field come from meteoric water that is recharged at an elevation of 1300-1500 masl. Geothermometers based on δ¹⁸O_H2O-SO4, water chemistry (T_Na-K-Ca) and gas chemistry (T_H2-Ar) show similar reservoir temperatures that range from 250 to 280 deg. C. δ¹⁸O, δD isotope composition of the steam vents at the cone of Sibayak mountain, having the value of -2.9 per mille for δ¹⁸O and -44.9 per mille for δ D, shows magmatic inputs. (author)

[en] The study was based on indonesia and global waste managament issue especially on non-biodegradable waste handling and the circular economy of the method to solve the problem. Non-biodegradable waste is a problem in the world and its management especially for non-recycled waste does not reflect the circular economy principle and not environmentally friendly. This needs a new method that can process this type of waste through an environmentally friendly recovery process. Zero Waste Management/Manajemen Sampah Zero (MASARO) technology presents a solution to this problem by processing non-recycled non-biodegradable waste through a plastic refinery unit in Non-Biodegradable Waste Management Installation/Instalasi Pengolahan Sampah Anorganik (IPSA). The application of the circular economy principle has been carried out in this MASARO plastic refinery where All non-biodegradable waste is processed into other useful products, such as: fuel, planting media, wood preservatives and organic pesticides. There is no non-biodegradable waste ended up in Temporary Waste Site (TPS) and Final Landfill (TPA). Therefore, MASARO plastic refinery is an environmentally friendly solotion for non-biodegradable waste and suitable for sustainable development. (paper)

[en] Polyhydroxybutyrate (PHB) films with highly porous structures were synthesized using a one phase system comprising of metal chloride/methanol/PHB/chloroform (MCl₂/CH₃OH/PHB/CHCl₃). SEM analyses confirmed that the MCl₂ (where M = Cu²⁺ or Ni²⁺) induced porous structures with pore sizes ranging from 0.3 - 2.0 μm. The average pore size increased with the increasing MCl₂ content. There existed weak physical interactions between the PHB chains and MCl₂ as revealed by FTIR and NMR spectroscopies. The residue of MCl₂ in the porous PHB film does not exert significant influence on the thermal stability of PHB. Nevertheless, the crystallinity of the prepared film is enhanced, as MCl₂ acts as the nucleation sites to promote the growth of spherullites. (paper)

[en] Liquid phase exfoliation (LPE) with surfactant-assisted is a method to produce graphene that used water and surfactant as solvent. Tea is one of possible surfactants that can be used in LPE of graphite as it reduced the surface tension energy of water (72.75 mJ m⁻²) to ∼40 – 50 mJ m⁻² which is suitable level to exfoliate graphite. Three different types of tea were used as surfactant through one-step production of graphene which were green tea (GT), black tea (BT) and oolong tea (OT). The exfoliation of graphite in each tea solutions were successful as the UV spectra of supernatant samples show peak at 270 nm which indicates the C – C bond of graphene flakes. Morphology analysis (AFM) of resulted graphene samples show that graphene sheets have sharp edges caused by sonication process. The effect of sonication time was being investigated in this work. Green tea has higher exponent factor of time (1.715) compare to black tea (1.033) and oolong tea (0.762) due to high quantity of small molecules of polyphenols present in green tea solution. Thus, it is better to used GT as surfactant in LPE of graphite compare to BT and OT. (paper)