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Higher education requires learning in the form of practice and research which is often carried out in the laboratories. The research completed in the laboratory usually produce wastewater which not only has a high organic content but also containing heavy metal ions such as Copper (Cu), Cadmium (Cd), and Lead (Pb). These heavy metal ions will harm the environment when directly disposed without being treated first. One of methods to reduce heavy metal ions level in laboratory wastewater is adsorption method using chitosan. Therefore, this research was focused on removal heavy metal ions in laboratory wastewater by adsorption method using a chitosan derived from fish scales. The objective of this research is to investigate the effect of pH on the removal of Cu, Cd, and Pb ions in the treatment of synthetic wastewater using chitosan. The effect of chitosan dose on the treatment of laboratory wastewater was also examined. Initially, the chitosan was applied in reducing the metal ions in synthetic wastewater. The synthetic wastewater was prepared using single-component and multicomponent of heavy metal ions samples. In this study, the pH was varied from 3-7 for application of chitosan on single and multicomponent synthetic wastewater experiments. The optimum of pH produced then used to remove the metal ions included in laboratory wastewater sample while the chitosan dose was varied 0.5-2 g/L. As the results, the highest removal percentage for the reduction of Cu, Cd, and Pb metal ions in single-component synthetic wastewater was at pH 7. However, the highest removal percentage for the reduction of Cu, Cd, and Pb metal ions in multicomponent synthetic wastewater were found in different pH, such as Cu ions at pH 5, Cd ions at pH 7, and Pb ions at pH 3. When applied to laboratory wastewater assessments with pH of 7 and chitosan doses of varied by 0.5-2 g/L, the highest percentage removal of Pb ions (93.75%) was reached when using chitosan dosage of 1.5 g/L; the highest percentage removal of Cu ions (28.99%) was obtained when using chitosan dosage of 2 g/L. Alas, the chitosan dose of 0.5-2 g/L did not have a significant effect on reducing of the Cd ions.

Empty Fruit Bunch (EFB) resulted from oil palm plantations and mills can be converted into ash through open combustion. The EFB ash then treated by simple calcination and used as a heterogeneous catalyst for biodiesel production. The characteristics of EFB ash were identified based on its elemental composition, porous structure, and active site size. The effectivity of the EFB ash as a catalyst was tested in a transesterification reaction of Refined Bleached Deodorized Palm Oil (RBDPO) with excess methanol (30 %-w) in various catalyst loads (in%-wt). The lab-scale experiments were conducted in a three-neck glass reactor, which was put on the hot plate stirrer at 450 rpm. The EFB ash performed the best as a catalyst by attaining optimal conversion at 65 °C for 1 h with a 16 %-wt of catalyst load. In this condition, most of the standard quality of biodiesel were complied with total glycerol under 0.24% and ester methyl contents up to 98.9 %. The characteristics tests showed that the properties and active side of the EFB ash are excellent after calcination at 600 for 5 h. The recyclability test of EFB ash as a catalyst showed high performance in two repetition cycles, each showing an increase in the yield of biodiesel, which was 92.21 % in cycle 2 and 91.23 % in cycle 3.

One of the main needs of humans is water, one source of water pollutantion is from dyes. Adsorption is the most popular method in removing pollutants as it is proven to be efficient. One of the dyes harmful to living things is malachite green. In this study, malachite green dye was removed using a layered double hydroxide (LDH) Zn-Al/magnetic biochar composite. The XRD, FTIR, BET, and VSM analyses show that the LDH Zn-Al, magnetic biochar, and LDH Zn-Al/magnetic biochar composite were successfully produced. The surface area of the Zn-Al/magnetic biochar composite made up of LDH increased from 9.621 m2/g to 99.473 m2/g. The point of zero charge of LDH Zn-Al and magnetic biochar were at pH 6, whereas the composite of these two materials was at pH 7. For LDH Zn-Al, magnetic biochar, and composite LDH Zn-Al/magnetic biochar, pH 8 is the ideal value for adsorption of malachite green. PSO (pseudo-second order) kinetics is the best-fit model. LDH Zn-Al, magnetic biochar, and LDH Zn-Al/magnetic biochar composite had adsorption capacities of 14.472, 15.552, and 25.907 mg/g, respectively, at a temperature of 60°C. Regeneration showed the LDH Zn-Al/magnetic biochar composite had superior and more effective ability compared to LDH Zn-Al and magnetic biochar.

Water is one of the most basic human needs, and dyes are one of the sources of water pollution. Since adsorption has proven to be effective in removing contaminants, it is the most widely used technique. In this adsorption, a LDH Zn-Al /magnetic biochar composite was used for dye removal. Zn-Al LDH, magnetic biochar, and LDH Zn-Al/biochar magnetic composite were successfully synthesized, based on XRD and FTIR studies. XRD analysis of the Zn-Al LDH material shows diffractions of (003), (006), (101), (012), (015), (107), and (110) around the 2theta angle at 10.29°, 20.07°, 29.59°, 32.12°, 34.02°, 48.06°, and 60.16° which are characteristic of LDH materials. In magnetic biochar and LDH Zn-Al/magnet biochar composites diffraction (220), (311), (422) and (440) at 2theta around 24.9°, 35°, 63° and 68.4° in these materials indicate the characteristics of carbon-based materials from biochar. FTIR analysis showed the appearance of a vibration peak at 1404cm−1 indicating the presence of C H groups contained in biochar. The characteristic double-layer hydroxy (M-O) vibrations below 1000 cm−1 also indicated that the composite preparation process had been successful. The study’s results show that cationic dyes are more easily adsorbed than anionic dyes. Specifically, the LDH Zn-Al/Magnetic Biochar composite more extensively absorbs the cationic dye malachite green.

Biodiesel production is generally catalyzed by potassium methylate or sodium methylate catalysts based on KOH and NaOH and these catalysts are still imported. The search for a cheap and effective catalyst continues to be carried out by researchers. One of the catalyst support materials currently in use involves impregnating K2CO3with various substances, resulting in a heterogeneous catalyst. In this study, it was tried to use K2CO3dissolved in methanol to produce a homogeneous potassium methylate catalyst. Potassium methylate-based homogeneous catalyst K2CO3-methanol is proven to have a very high function in the transesterificati on reaction of Refined Bleached Deodorized Palm Oil (RBDPO) into biodiesel, this is evidenced by the use of a catalyst percentage of2% w and 30% w methanol to the weight of RBDPO resulting in an acid content in biodiesel of only 0.12% and a total glycerol of0.124% in reaction time 3 hours, with the purity of the methyl ester in biodiesel reaching 98.80%. Meanwhile, for the calculation of homogeneous reaction kinetics, a reaction rate equation is produced where the order of the RBDPO transesterification reaction is order 2 (two) and the reaction rate constant is 0.0044.

The research activities carried out in the laboratory produce complex wastewater which most likely damage the environmental ecosystem if it is directly disposed of without treatment. Wastewater treatment in this study aimed to reduce the pollutant load contained in laboratory wastewater by using combination methods of Advanced Oxidation Processes (AOPs), and chemical-physical treatment namely coagulation and adsorption processes. The Photo-Fenton process was selected as one of AOPs applied in this treatment. The effect of molar ratio variation and irradiation time in the Photo-Fenton process on the pollution load in the form of pH, COD, BOD, TSS, and heavy metals Zn, Cu, Cr, Pb, and Fe was studied in this research. The results of the analysis of untreated laboratory wastewater samples showed that laboratory wastewater did not meet the wastewater quality standards regulated in the Regulation of the Minister of Environment of the Republic of Indonesia No. 5 of 2014 on Wastewater Quality Standards. In this study, laboratory wastewater was treated using the pre-treatment method of coagulation with alum and adsorption with activated carbon. The best results in this study were obtained in the final adsorption results after treatment with the Photo-Fenton method using a molar ratio of 1: 300 for 60 minutes in which several parameters such as pH, Zn, Cu, Pb, and Fe had met environmental quality standards with the value of each parameter of 7; 0.01 mg/L; 2.9 mg/L; 0.03 mg/L; and 3.15 mg/L respectively. Meanwhile, the percentage reduction of COD, BOD, and TSS parameters was 87.49%, 87.02%, and 72.45% respectively.

Biodiesel production using novel glycerol and potassium carbonate-based catalysts has not been developed under the Taguchi technique. This study aims to determine the most influential parameter in biodiesel production from refined bleach-deodorized palm oil (RBDPO) using DES K2CO3-Glycerol as the novel catalyst. The raw material was subjected to transesterification at the desired reaction parameters estimated by the orthogonal 16-run (L16) approach with 2 levels and 4 factors of the Taguchi technique. Signal-to-noise ratio (SNR) and ANOVA were used to confirm the predicted value. From the results, the catalyst is the most influential variable in the TG value of biodiesel, placed in the first rank of the influence factor. Biodiesel production with a minimum total glycerol value (0.210%) using DES K2CO3-Glycerol as a catalyst is most optimally produced at 95 °C for 4 h and 400 rpm using 30 wt% methanol and 4 wt% catalysts achieved by the Taguchi technique. The biodiesel obtained from RBDPO complies with the required international standards. Doi: 10.28991/ESJ-2023-07-03-018 Full Text: PDF

The coal gasification process in this study aims to increase the quality of low-rank coal (LRC) from lignite type to coal with semi-anthracite and anthracite grades with higher fixed carbon values. The gasification process is carried out at temperatures between 700-900oC. In the initial stages of the study, the relationship between the increase in gasification temperature with the mass of coal and the gasification process time. The proximate and ultimate analysis is carried out to determine the characteristics of the raw materials used and the coal char produced from combustion. The analysis results are used to calculate the fuel ratio, where the fuel ratio is a parameter to determine the grade of coal. In addition, an SEM-spot EDS analysis was carried out on the gasified coal solids to ensure the fixed carbon content produced from the above process. The results showed that the gasification process could raise the grade of LRC into char products with semi-anthracite to anthracite, where the fuel ratio reached 10.84. From the product analysis results, the LRC coal gasification results using SEM-EDS showed that carbon reached 98.58%. The remaining inorganic elements in the product are less than 1.5%, such as Al, Si and K.

The compatibility problems become the main concern in the utilization of biodiesel especially regarding degradation and corrosion. The present study is conducted to describe the corrosion behaviour that occurs in steel tanks after contact with palm-based biodiesel for a period of 7 months. The storage tank used is respectively made of galvanised steel (GS), carbon steel (CS) and stainless steel (SS). It is performed in vertical cylinders with a floating-roof model. In every 30 days of storage time, the profile changes in the wall, roof and base surface of each tank were observed. The oil fuel properties were monitored in the parameter of viscosity, acid numbers, water content and oil colour. The topographic profiles on the surface of the walls and bottom of each tank wetted by biodiesel were examined over three zones inside the tanks using an endoscope imager. The main results of this study indicate that tank steel with different protective layers exhibits different types of corrosion. The corrosion was localized in SS tanks but generalized in GS and CS tanks. The oil contamination in SS tanks was relatively lower than that in CS and GS tanks. The type of corrosion performed differently in different zones on the inside of the tank. The potential for leaks is greater at the base than on the walls and roof of the storage tank.

Wastewater generated from pulp and paper production still contains pollutants and contaminants, so appropriate and economical materials are needed to reduce pollutants by using adsorbents from bottom ash. This study examines the characteristics of bottom ash and pulp and paper wastewater, the effect of stirring time, stirring speed, and adsorbent activation temperature on decreasing environmental parameters of wastewater. The synthesis of bottom ash as an adsorbent was carried out by heating at 100 and 200 °C for 1 hour. The wastewater treatment process with maximum yield occurs at a stirring speed of 100 rpm for 50 min. The use of bottom ash without heating as an adsorbent in the pulp and paper wastewater treatment process has reduced TSS 77.5%, COD 85.72%, chloride 26.9%, TDS 1143 ppm, and EC 2180 s/cm, which have met the environmental quality standards.

Heavy metal is a type of metal that has a high density and high toxicity when consumed by living things, especially humans. To prevent the impact of environmental pollution, optimal handling of wastewater containing heavy metals is required, including the wastewater from laboratories. This research aimed to study the effect of pH, catalyst dose, and irradiation time on the reduction of Copper (Cu), Iron (Fe), and Lead (Pb) heavy metals and their application to laboratory wastewater treatment. Among the Advanced Oxidation Processes (AOPs) methods, photocatalysis was chosen to reduce the level of Cu, Fe, and Pb heavy metals where ZnO is used as a photocatalyst and the sunlight as a light source. To determine the effect of pH, catalyst dose, and time on the reduction of heavy metal levels, firstly, this research used synthetic the wastewater containing Cu, Fe, or Pb heavy metals. On the basis of the experimental results, it is concluded that the pH value, catalyst dose, and time affect the photocatalytic process, decreasing the levels of Cu, Fe, and Pb metals. The optimum pH value obtained for Cu was at pH 7-8, for Fe it was at pH 6, and for Pb it was at pH 8; in turn, the metal removal percentages were 99.46%, 99.91%, and 99.70%, respectively. In the photocatalysis of synthetic wastewater, high removal percentage of more than 99% was achieved by using 0.1 g/L catalyst. The optimum decrease of metals occurred in the first 15 minutes of solar irradiation where the removal percentage was close to 100%. In this study, the application of ZnO photocatalyst under solar irradiation can reduce the heavy metals content in the laboratory wastewater by almost 100%, which meets the environmental quality standard for Cu, Fe, and Pb.

Laboratory wastewater contains organic and inorganic compounds that are harmful to the environment when dispose without prior treatment. Beside of the high COD and BOD values, the laboratory wastewater also contains metals such as iron (Fe), zinc (Zn), copper (Cu), chromium (Cr), and lead (Pb) which categorizes as dangerous waste material and can pollute the groundwater. Although the quantity of wastewater produced by the laboratory is relatively small, it has a real impact on the environment around the laboratory. However, the wastewater has to treat properly before discharge into the environment. The aim of the research was to study the laboratory wastewater treatment by using Fenton's reagent with coagulation and adsorption pretreatment. In the pretreatment with coagulation, three types of coagulants are used, namely PAC (Poly Aluminum Chloride), ACH (Aluminum Chlorohydrate) and Aluminum Sulfate (AS) with their respective concentrations of 10-80 ppm. The highest percentage of average pollutant removal of 58.21% was found when applied 80 ppm of AS. The pretreatment was continued by adsorption with activated carbon and zeolite adsorbents within 60-120 minutes of mixing time. It was detected, the most optimum adsorbent was activated carbon with average pollutant removal of 50.22% within 1 hour of mixing time. Processing was extended by utilized Fenton's reagent using a variation of the molar ratio between 1:100-1:400. It was obtained that the best molar ratio to degrade the laboratory wastewater is 1:300 with an average removal of pollutant of 43.45%. As a result of laboratory wastewater treatment using combine Fenton's reagent and coagulation-adsorption pretreatment, an average pollutant removal of 90.81% was obtained. The final content of COD, BOD, TSS, as well as Cu and Pb metal has met the environmental quality standard.

Coal hauling, loading, and transportation activities impacted the emergence of coal dust which is harmful to health. Coal dust exposed from coal unloading stations and coal waterway transportation is escaped attention. This study aimed to determine the characteristics of coal dust, the influence of climate parameters on the spread of coal dust, and its impact on the health of children under five in the exposed area. Coal dust characteristics and concentrations of PM PM2.5 and PM10 were analyzed from ten points spread across three mining companies (A, B, and C). The effect of climate parameters on PM2.5 and PM10 was tested statistically. The results of the chemical analysis revealed that coal dust was dominated by the high content of Si, Al, S, and Fe. The concentration of PM2.5 and PM10 is affected by wind speed. PM2.5 and PM10 can exceed the annual threshold value, which has caused a high incidence of respiratory problems in two sub-districts, namely Makrayu and Gandus.

Adsorption is regarded as one of the most promising and straightforward strategies for reducing organic pollutants from wastewater effluents. The use of adsorbents from economical raw materials, even those from waste, is one recent concern. This study aims to test the effectiveness of biomass-based fly ash in treating liquid waste from pulp and paper production activities. Fly ash (FA) performance for adsorption was tested by varying the ratio of adsorbent with wastewater by 20, 40, 60, and 80 g/L. The adsorbents' performance was then compared between the application of FA directly (without activation) and adsorbents that were previously calcinated in 100 °C and 200 °C. Samples of pulp and paper liquid waste are placed on the erlenmeyer flask and stirred using a jar test with speeds varying by 100, 200, and 300 rpm. The results showed that FA is potential directly used with no thermal treatment as an adsorbent in treating liquid waste in the pulp and paper industry. It was effectively used with a dosage of 20 g/L and a 100 rpm fatigue speed with a contact time of 10 min. The quality changes of several wastewater parameters were found with a 92.5% reduction in TSS, 83.31% in COD, 19.99% in chlorides, 95.41% in NH3, and 19.6% in TDS, 19.6% in EC. Those parameters have successfully complied with the regulation standard of Indonesia (SNI) for wastewater.

Biodiesel is currently preferred for consumption and has been widely used as a substitute for diesel. This study aimed to determine the effect of various methanol-to-oil ratios in the esterification process and also the effect of hydrotalcite catalyst weight on the transesterification product. The catalyst was characterized with SEM, XRD, FTIR, and TG-DTG-DTA. The esterification process was operated at various oil-to-methanol ratios, i.e., 1:12-1:36 and the transesterification was performed using several catalyst weights, 0.5%-2.5%. The results showed that the optimum conditions of esterification were at the 1:30 molar ratio of oil-to-methanol, which decreased the amount of acid number by 95.75%, while the optimum condition of transesterification was at 1.5% catalyst weight. The characteristics of biodiesel using 0.5-2% hydrotalcite catalyst (acid number, total glycerol, free glycerol, ester levels, viscosity, density, oxidation stability) have met the Indonesian biodiesel standard of SNI-04-7182-2012.

Fuel contamination is a major issue that comes with the utilization of biodiesel. Microbial growth is one of the primary causes of contamination during fuel handling and storage. This work attempts to identify the types, shapes, and growth profiles of microorganisms on fuel samples. The morphology of microbial colonies is presented in order to analyze the potential of fuel contamination. The diesel, biodiesel, and blends are stored in stainless steel (SS) and glass tanks, where each is placed indoors and outdoors during the 90 days of storage time. The morphology of microbial colonies is observed through a microscope with a magnification of 1000× and the quantity is calculated by a digital colony counter. Microbial contamination in all samples is considered as high contamination where the Colony Forming Unit (CFU) is greater than 105 L−1. Colony forms are far more assorted in blends than in pure diesel (B0) and neat biodiesel (B100). The transformation of microbial colonies accelerates after 60 days of storage time. The results reveal that the number of bacterial colonies that grow in B20 is higher and more varied, nevertheless, the contamination in B100 is significantly higher. This is indicated by a 1.5-fold rise in B20 acidity and a 2.5-fold increase in water content compared to the initial condition.

Mercury is a hazardous element because of its toxicity and harmful effects on human health. Various traditional and low-cost methods have been developed to remove mercury from wastewater. This study used local raw material as an alternative adsorbent to treat mercury-contaminated wastewater. Activated bentonite was prepared using different chemical activators (H3PO4, HCl, and ZnCl2) in various concentrations. Then, it was dried at 200°C for an hour. The materials were characterized by SEM-EDS. Its percent removal and isotherm models were analyzed. In this study, the most effective activator was H3PO4 and the experimental data matched the Freundlich model.

Pulp and paper industry fly ash is categorized as B3 waste, namely hazardous and toxic waste. Liquid waste produced by the pulp and paper industry contains pollutants that are toxic and can cause pathological and histopathological changes in important tissues such as the gills of fish that live in the waters around the disposal. The purpose of this study was to analyze the histology of tilapia on the performance results of fly ash adsorbents in the management of liquid waste in the pulp and paper industry. The research method has 6 treatments, namely the ratio of fly ash to pulp and paper liquid waste (20 g; 1 L) namely P0: 100 % well water control, P1: lowest liquid waste 5 % + 9.5 % well water, P2: 5 % liquid waste fly ash adsorbent + 95 % well water, P3: 6.25 % liquid waste fly ash adsorbent + 93.75 % well water, P4: 7.5 % liquid waste fly ash adsorbent + 92.5 L of well water, P5: 8.75 % fly ash adsorbent + 91.25 % well water, P6: 10 % fly ash adsorbent + 9 % well water. Water quality measurements such as temperature, NH3, pH and DO were carried out. Observation of gill histology used microtechnical method which includes deparaffinization and histological staining (HE). Analysis was carried out on changes in cell morphology in gill tissue. The results showed that the morphology of gill cells in liquid waste pulp and paper 5 % found gill damage in the form of congestion, secondary lamella fusion, secondary filament rupture and goblet proliferation occurred in the treatment of wastewater treatment while Fly ash adsorbent 5 % damaged gills in the form of congestion and fusion of secondary lamellae. From the results of the Fly ash functions can reduce damage to body organs in fish, especially on the gills so that it can reduce the number of deaths in fish compared to treatment without the use of fly ash.

Coal is a fossil energy source that is widely used as a soild fuel in many sectors. The development of indirect coal liquefaction technology is one type of technology used to convert coal into a liquid fuel product in the form of coal oil with characteristics resemble petroleum fuels. Coal oil production can be an alternative fuel source for future energy needs. In this study, the indirect liquefaction process of coal (calorific value = 6400 kcal/kg) was done in the fluidized bed reactor by heating the reactor with an electric furnace, where the process took place at temperature 350oC - 500oC and the catalyst weight was varied into 0%, 5%, 10%, and 15%. Air with a flow rate 2 LPM is flowed during the process and the lenght of the process was 60 minutes. From this research, the best characteristics of coal oil produced at a temperature of 400oC - 450oC with a catalyst weight of 15%. The characteristics of the coal oil obtained have a density of 0.852 g / cm3, specific gravity of 0.853 and oAPI gravity of 34.41. The results of GC-MS analysis was known that 46.15% of the composition of hydrocarbons in coal oil is the fraction of gasoline.

One of the main needs of humans is water, one source of water pollutantion is from dyes. Adsorption is the most popular method in removing pollutants as it is proven to be efficient. One of the dyes harmful to living things is malachite green. In this study, malachite green dye was removed using a layered double hydroxide (LDH) Zn-Al/magnetic biochar composite. The XRD, FTIR, BET, and VSM analyses show that the LDH Zn-Al, magnetic biochar, and LDH Zn-Al/magnetic biochar composite were successfully produced. The surface area of the Zn-Al/magnetic biochar composite made up of LDH increased from 9.621 m²/g to 99.473 m²/g. The point of zero charge of LDH Zn-Al and magnetic biochar were at pH 6, whereas the composite of these two materials was at pH 7. For LDH Zn-Al, magnetic biochar, and composite LDH Zn-Al/magnetic biochar, pH 8 is the ideal value for adsorption of malachite green. PSO (pseudo-second order) kinetics is the best-fit model. LDH Zn-Al, magnetic biochar, and LDH Zn- Al/magnetic biochar composite had adsorption capacities of 14.472, 15.552, and 25.907 mg/g, respectively, at a temperature of 60°C. Regeneration showed the LDH Zn-Al/magnetic biochar composite had superior and more effective ability compared to LDH Zn-Al and magnetic biochar. [ABSTRACT FROM AUTHOR]

Spent acid waste is produced in the petroleum processing industry at the alkylation process unit that requires sulfuric acid as a catalyst to produce iso-octane. Therefore, spent acid contains sulfuric acid attached to a long chain carbon and other compounds. This compound is corrosive and has a pH below 1.0, so that it cannot be directly discharged into the environment. The processing and utilization of spent acid to meet environmental quality standards need to be conducted. This study aimed to conduct waste treatment of spent acid and to recover sulfuric acid from the spent acid solution because the level of H2SO4 is high at about 82%, then the sulfuric acid can be reused in the alkylation process or other processes. Adsorption method was selected to process the waste using bentonite as adsorbent in 3 stages adsorption columns. The results showed that the recovery of H2SO4 was successful in which the purity of H2SO4 generated after distillation reached 94.94%.