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Abstract Selective lithium recovery from a mixture of LFP-NMC spent lithium batteries presents significant challenges due to differing structures and elemental compositions of the batteries. These differences necessitate a distinct recycling pathway for each, complicating the process for the mixture. This study explored a carbothermal reduction approach combined with water leaching under atmospheric conditions to achieve a selective lithium recovery. For individual NMC black mass, at the optimal carbothermal conditions (950 °C, 15 °C/min, 2 h), lithium recovery of 95.7 ± 0.31% with 100% selectivity could be achieved. However, when the black mass was mixed with that of LFP in a 50:50 ratio, the recovery dropped to 9.78 ± 0.44%. Solid-state reactions during carbothermal process resulted in the formation of highly insoluble Li3PO4, and Fe-Ni-Co/Ni-Co alloys, which hinder lithium dissolution. To address these challenges, Na2CO3 was introduced as an additive to suppress Li3PO4. The addition of Na2CO3 to the 50:50 ratio of LFP-NMC black mass, increased lithium recovery to 59.47% with 100% selectivity. This enhancement was due to the stabilization of lithium as Li2CO3, a water-soluble compound. The results demonstrated that addition of Na2CO3 is a promising strategy for improving lithium recovery from mixed LFP-NMC batteries, providing a potential pathway for a more efficient recycling process.

This study uses electrocoagulation to investigate reducing heavy metal content in wastewater from discharging spent batteries. ICP-OES analysis shows that heavy metals exceed the environmental water standard. The electrocoagulation procedure was conducted within a reactor with a 500 mL volume and a rectifier with a 5 A current capacity. Three types of electrode material combinations were used: iron (Fe) and aluminium (Al) as well as Fe-Fe, Al-Al, and Fe-Al pairs with 1 cm in the distance by parallel monopolar cells. Alternating current was used with 30, 40, and 50 A/m2 current density. The best result shown in the Fe-Al electrode pair combination system at 40 A/m2 for 30 min contact time and removal efficiencies for Co, Cd, Ni, Zn, and As is 98.76, 90.73, 99.32, 97.93, and 97.78%, respectively, while for Hg it is 31.84%, even though only Cd is above the standard limit. The heavy metal bearing was confirmed using SEM-EDS in the floc and the precipitate residue. The dissolved electrode materials and electrical energy consumed are 0.32 g and 0.109 kWh/m3, respectively. This method can be a good alternative for treating wastewater compared to direct current electrocoagulation, where the electrode and energy will be less consumed.

Abstract Worldwide, silicified woods are found in many geological formations. Significantly, the organic materials of wood are no longer dominant; almost all wood fossils have been mineralized into inorganic silica materials. These unique geological processes must be understood to develop better understanding on organic material fossilization, particularly in the micron scale. Therefore, our aim was to characterize the composition of silicified wood using comprehensive microanalysis. The methods utilized were XRF, ICP-MS, XRD, FTIR, and FE-EPMA. Specimens are from Jasinga, West Java, Indonesia. The results showed that wood silicification was controlled by the infiltration of silica from the host rock into the spaces of the wood structure. In Jasinga, they are controlled by Pliocene tuffaceous sedimentary rocks. The ratio of silica phases revealed a trend in the degree of silicification. Besides silica, the distribution of trace elements also demonstrates the geochemical interaction between the wood fossil and host rock. Wood fossils are affected by the gradual replacement of organic carbon-based materials with silica through silicification. Silica enrichment occurs in the internal of wood, facilitates permineralization and recrystallization. Silica replaces organic material and preserves the wood structures. The microanalytical approach provides comprehensive perspectives on wood petrification, leads to better insights for paleontological studies.

Background: Diabetes mellitus is a metabolic disorder characterized by elevated blood sugar levels and resulting from deviations in either insulin secretion, insulin action, or both. Prolonged hyperglycemia can lead to various complications, including diabetic retinopathy. The main risk factors for developing diabetic retinopathy are uncontrolled diabetes mellitus, hypertension, and dyslipidemia. Aims: To determine the correlation between hypertension and the severity of diabetic retinopathy in diabetes mellitus patients at Waled Regional General Hospital, Cirebon, from 2020 to 2023. Methods: This study used an analytical observational method with a cross-sectional design. We collected data from the medical records of patients with diabetic retinopathy at Waled Regional General Hospital from 2020 to 2023. This study employed total sampling as its sampling technique. We performed univariate analysis to determine the frequency distribution of the samples and bivariate analysis using the Spearman correlation test. Results: Out of 50 diabetic retinopathy patients, the majority suffered from proliferative diabetic retinopathy (PDR), with 22 (44%) patients. The most common blood pressure level among the patients was grade 2 hypertension, with 19 (38%) patients. The bivariate analysis in this study showed a P-value of 0.091 and an r-value of 0.242. Conclusion: There is no significant correlation between hypertension and the severity of diabetic retinopathy in diabetes mellitus patients at Waled Regional General Hospital from 2020 to 2023, with a positive correlation direction (p-value: 0.091 and r-value: 0.242). Received: 25 September 2024 | Reviewed: 16 October 2024 | Revised: 30 November 2024 | Accepted: 12 December 2024.

Every year, the production of rice straw and cow paunch content is abundant and 80 % of them has not been utilized. This study aimed to determine the potency of ensiling treatment on them in producing bioethanol. The novelty of this study is the utilization of cow paunch content as biomass and source of microbial fiber degradation. In this study, there were six groups of treatments. Bioethanol fermentation used Saccharomyces cerevisiae. Results, ensiling treatment significantly affected (p

Halmahera Island in Indonesia holds great potential for nickel laterite due to its geological setting. As the product of chemical weathering, nickel laterite can be divided into saprolite and limonite. Despite containing invaluable elements like nickel and cobalt, limonite ore is seldom used in metal production. This study evaluates these two elements’ leaching behavior and kinetics from the Halmahera deposit. Limonite ore was leached using 50 mL of 0.5 M sulfuric acid at an S/L ratio of 10% and 20%. The leaching process was conducted at 30°C, 50°C, and 80°C. The experimental results showed that the highest recovery for cobalt and nickel was 100% in the adequate presence of H+ ions. The result shows that sulfuric acid is more selective to cobalt than a nickel. The shrinking core ash diffusion model represents the leaching kinetics of cobalt, while nickel recovery follows the Kröger-Ziegler kinetics model.

Minerals containing TiO2 are common in Indonesia, such as ilmenite in iron sand deposits scattered along the country's coasts. Ilmenite is an important source of titanium. One method for making TiO2 from ilmenite is by solubilizing both the Fe and Ti elements in HCl and then immediately hydrolyze the Ti. The leaching of low-grade ilmenite (ground to 0.177-0.149 mm) is studied kinetically by HCl in a stirred reactor. The research was conducted using the caustic fusion method followed by HCl leaching. The leaching reaction kinetics at the optimum conditions are analyzed using response surface methodology (RSM) with a second-order polynomial equation model and SSE with the shrinking core model (SCM). The results showed that HCl concentration and leaching time were directly proportional to the leached titanium concentration. In contrast, the leaching temperature was inversely proportional. The optimum operating conditions were obtained at a temperature of 30 °C, 9 M HCl, and 120 min of leaching time. The shrinking core model is a better representation of the kinetics than RSM with a second-order polynomial equation model. Based on SCM, the rate of the leaching reaction of titanium from low-grade ilmenite is controlled by diffusion through the ash layer.

Nickel laterite is typically processed into ferronickel through a pyrometallurgical method involving high temperatures and the use of fossil fuels, such as coals or cokes. Unfortunately, this process releases emissions like CO2, SO2, and NOx into the environment. This study explores a sustainable approach for nickel laterite processing by investigating low-temperature selective reduction using various biomass reductants. The materials, including saprolitic nickel ore and biomass types (palm kernel shell charcoal or PSC, lamtoro wood charcoal, coconut shell charcoal, and rubber wood charcoal), undergo pelletization, selective reduction at 1150 °C, and wet magnetic separation. PSC biomass is superior to other biomass due to its 217.2 m2/g specific surface area value. Optimal conditions were achieved using 0.3 stoichiometric PSC, along with the addition of 10 wt% of sodium sulfate as an additive. This has led to a nickel mass fraction of 26.0 wt% and a recovery rate of 27.4 %.

Magnetite, a widely synthesized compound utilized as an adsorbent in various processes, exhibits reduced adsorption efficiency due to aggregation in aqueous solutions. Addressing this limitation, modification of magnetite is necessary to mitigate agglomeration and enhance adsorption capacity. Herein, we propose the utilization of gaharu leaf extract for magnetite modification, leveraging its abundance as a byproduct of essential oil production and rich secondary metabolite content, which serves as a stabilizing agent in synthesis processes. Magnetite (M) and gaharu leaf extract-modified magnetite (MEDG) were synthesized and evaluated as adsorbents for methyl orange (MO) textile dyes. Characterization via FTIR, PSA, SEM-EDX, XRD, and VSM revealed distinctive features of MEDG, including vibrational peaks corresponding to organic functional groups derived from the secondary metabolites present in the gaharu leaf extract. These functional groups actively participate in the adsorption process and prevent magnetite aggregation. MEDG exhibited a particle size of 4408.7 nm, compared to 4625 nm for M, with both exhibiting face-centered cubic (fcc) crystal structures. Additionally, MEDG demonstrated a crystallinity percentage of 92.49 % and saturation magnetization of 34.43 emu/g, attributed to the incorporation of gaharu leaf extract. Adsorption studies demonstrated that MEDG and gaharu leaf simplicia (SDG) achieved maximal adsorption of MO at pH 3 for 60 min and pH 4 for 70 min, respectively, with an adsorption efficiency of 95–99 % for a 5 ppm MO solution. The adsorption kinetics followed Ho’s pseudo-second-order model, and the isotherm conformed to Freundlich’s model. Furthermore, M and MEDG exhibited high reusability, with up to 5 cycles of reuse, while SDG demonstrated 3 cycles. However, the adsorption efficiency decreased to 87 % for MEDG and 85.19 % for SDG upon the fifth repetition. In conclusion, modification of magnetite with gaharu leaf extract enhances its adsorption capacity, offering economic advantages over pure magnetite due to increased surface area and active sites.

Almost all farmers are unaware that rice straw and paunch manure are potential feedstocks for bioethanol besides organic fertilizer, biochar, and biogas. Farmers' perceptions regarding the multiattributes of bioethanol development are still underestimated, indicating that farmers are still indecisive about the potential use of rice straw and paunch manure as feedstock for bioethanol. They still need extension and training to improve their knowledge. The Location Quotient (LQ) value of rice straw and cattle paunch manure is > 1, indicating that Karanganyar Regency could become a base for bioethanol development from rice straw and cattle paunch manure.

Penelitian ini bertujuan untuk dapat melihat gambaran self determination siswa dalam perencanaan karir. Untuk memperoleh gambaran determinasi diri siswa peneliti melakukan penelitian deskriptif dengan pendekatan kuantitatif. Analisis data dalam penelitian ini adalah univariat. Dari analisis yang dilakukan diperoleh hasil bahwa siswa SMK Negeri 2 Lhokseumawe memiliki determinasi diri pada kategori rendah sebanyak 51 siswa (54,8%). Kemudian berdasarkan aspek determinasi diri terlihat aspek kompetensi (52,2%) dan kemandirian (55,1%) masuk dalam kategori rendah. Sedangkan keterhubungan memperoleh kategori yang tinggi (61,9%). Selanjutnya hasil berdasarkan jenis kelamin, siswa SMK N 2 Lhokseumawe baik perempuan maupun laki-laki memiliki determinasi diri pada kategori rendah yaitu dengan persentase 50,7%.Berdasarkan jurusan siswa dengan jurusan tata busana memiliki determinasi diri tinggi (52%) sedangkan paling rendah pada jurusan tata boga sebesar 75%.

Papaya California (Carica papaya L) is one of the agricultural commodities in the tropics and has a very big opportunity to develop in Indonesia as an agribusiness venture with quite promising prospects. So the quality of papaya fruit is determined by the level of maturity of the fruit, the hardness of the fruit, and its appearance. Papaya fruit undergoes a marked change in color during the ripening process, which indicates chemical changes in the fruit. The change in papaya color from green to yellow is due to the loss of chlorophyll. During storage, the papaya fruit is initially green, then turns slightly yellow. The longer the storage color, the changes to mature the yellow. The process of classifying papaya fruit's ripeness level is usually done manually by business actors, that is, by simply looking at the color of the papaya with the normal eye. Based on the problems that exist in classifying the ripeness level of papaya fruit, in this research, we create a system that can be used to classify papaya fruit skin color using a digital image processing approach. The method used to classify the maturity level of papaya fruit is the Convolutional Neural Network (CNN) Architecture to classify the texture and color of the fruit. This study uses eight transfer learning architectures with 216 simulations with parameter constraints such as optimizer, learning rate, batch size, number of layers, epoch, and dense and can classify the ripeness level of the papaya fruit with a fairly high accuracy of 97%. Farmers use the results of the research in classifying papaya fruit to be harvested by differentiating the maturity level of the fruit more accurately and maintaining the quality of the papaya fruit.

This study examines the potential use of the spent catalyst as a raw material for rechargeable batteries. The spent catalyst Ni/γ-Al2O3 still contains relatively high amounts of nickel. This indicates the potential use of the spent catalyst to be leached and purified for synthesizing nickel-based compounds so that it can be applied to rechargeable battery cathodes. In this study, the spent catalyst leaching process employed four types of organic acids: citric acid, lactic acid, oxalic acid, and acetic acid. The spent catalyst was leached under atmospheric conditions and room temperature. Organic acid concentrations were also varied at 0.1, 0.5, 1, and 2 M. The leaching process took place for 240 minutes, where sampling was conducted periodically at 30, 60, 120, 180, and 240 minutes. Experimental results showed that Ni (II) and Al (III) ions were successfully leached to the maximum when using 2M citric acids at a leaching time of 240 minutes. The conditions succeeded in leaching Ni (II) and Al (III) ions of 357.8 and 1,975.4 ppm, respectively. Organic acid, notably citric acid, has excellent potential for further development. Citric acid, as a solvent, has the ability to leach metal ions with high recovery. In addition, this acid is categorized as an eco-friendly and green solvent compared to inorganic acid. Thus, the leaching process can take place without harming the environment.

Replacing metallurgical coke with greener material is a long-term challenge in pyrometallurgy. With the fact of biomass abundance in Indonesia, the usage of bio-char as a replacement for coke resulted from coal has been an intensive study. This study compared the performance between anthracite coal and coconut shell charcoal for nickel laterite reduction using the Equilibrium module on FactSage software simulation. The simulation was done by inputting a 4:4:1:20 weight ratio of nickel laterite ore, reductant (coal or coconut shell charcoal), lime and air, respectively. The temperature studied was 1300°C to 1700°C, and the pressure was atmospheric. The result shows that coconut shell charcoal has the potential to substitute anthracite coal as a reductant material in blast furnace processes. Anthracite coal consistently gives better results on the metal phase product with higher liquid metal yield and higher nickel and iron content. However, the coconut shell charcoal posseses the potential as a substitute material with temperatures above 1400°C regarding to the higher nickel concentration compared to anthracite coal. The resulting nickel and iron concentrations can reach above 2% and 96%, respectively, which is the required characteristics of a nickel pig iron product.

Electric Arc Furnace (EAF) waste contains 50-60% Zn. EAF waste synthesis has the potential to produce ZnO, which can be used in a variety of applications. The hydrothermal method is used in the synthesis, with time variations of 3 and 6 hours and temperature variations of 120 °C, 150 °C and 200 °C using precipitating reagents in the form of sodium hydroxide (NaOH) and oxalic acid (C2H2O4). UV-Vis spectrophotometer characterization result shows the absorbance value at 365 nm, which is the absorbance characteristic of ZnO material. The result of increasing the Zn element was revealed by XRF characterization. The XRD characterization revealed zinc oxalate dehydrates. This result depicts the hydrothermal with the oxalic acid solvent used to produce zinc oxalate dehydration at various temperatures and time variations.

Snake fruit peel is an organic waste that is often not utilized, while the flower of the butterfly pea is known as a natural dye for food and beverages. The COVID-19 pandemic causes susceptibility to the human body. Therefore, it is necessary to process healthy drinks in order to utilize organic waste. This community service program activity aims to introduce fermented food processing to the community, especially the Family Welfare Development (PKK) Group RT 3 RW 3, Ngijo Village, Gunungpati District, Semarang City by utilizing snake fruit peel (Salacca zalacca) and butterfly pea flower (Clitoria ternatea) as kombucha tea. The method of this program is in the form of delivering material either through posters, videos, demonstrations, and youtube links. A positive response was given by community after conducting a taste test on the product that was socialized in the form of many questions submitted including other alternative raw materials and the volume of kombucha tea served. This program has the potential to foster community motivation in entrepreneurship so that family income will increase.

UKBM Interactive Flipbook with Canva in English Subjects Discussion Text material was developed to answer problems in the field, namely the low student learning outcomes on Discussion Text material in schools based on the Semester Credit System. Based on the analysis of students' learning needs, data was obtained that UKBM had not fully prioritized the needs of students who were dominated by Generation Z who were very close to use technology as a source of learning. The objectives of this thesis are (1) to produce an interactive UKBM Flipbook product with Canva in the English subject for Discussion Text Materials at SMA Negeri 2 Blitar. (2) find out the feasibility of interactive UKBM Flipbook with Canva in the English subject Discussion Text material at SMA Negeri 2. This development uses the ADDIE model (Analysis, Design, Development, Implementation, Evaluation) From the results of the study, data was obtained that at the expert validation stage which was divided into Material Expert Validation by 95%, Media Expert validation by 85% and Design Expert Validation by 93%. If it is converted into the validity criteria adapted from Sugiyono (2011: 93) and very valid criteria are obtained for material validation, valid from Media experts and very valid by Design experts. So that as a whole the product development in the form of UKBM Interactive Flipbook with Canva in English subject, Discussion Text material, is very valid and feasible to use. Meanwhile, the results of the data analysis from the product trial showed that the percentage level of module validity was 88% with very valid criteria for 10 students as small group test respondents. Meanwhile, in the large group trial, the average percentage of module validity was 87% with very valid criteria for 33 students as respondents. It can be concluded that this interactive UKBM flipbook with Canva is very practical to use in learning English for Class XII Discussion text materia

In the process, data mining will extract valuable information by analyzing the existence of specific patterns or relationships from extensive data. One of the concerns of the new disease outbreak caused by the coronavirus (2019-nCoV) or commonly referred to as Covid-19, was officially designated as a global pandemic by the World Health Organization (WFO) on March 11, 2020. To break the transmission of Covid-19, the government carried out vaccinations for the Indonesian population. In the first period, the vaccination target will be for health workers with a total of 1.3 million people, public officers with 17.4 million people, and 21.5 million people. 19. The Data processed is only text data from Twitter application reviews that use Indonesian. Using the polarity of the Sentiment class Textblob, the sentiment class is positive, negative, and neutral. The data mining used is SVM, Naive Bayes, and Logistic Regression. As for this research in the form of knowledge of sentiment in the community towards vaccination activities, the results of this study get 43% positive sentiment, 40.8% negative, and 16.2% negative by testing the classification algorithm, Logistic Regression accuracy of 87%, SVM 86, 4%, and Naive Bayes, 40% of these results, can be seen that the Indonesian people have a positive sentiment towards the covid-19 vaccine.

The performance and kinetic of saprolitic laterite reduction using palm kernel shell charcoal and anthracite were studied. The anthracite coal represents the conventional high-grade carbon content matter, and palm kernel shell charcoal represents biomass-based reductant. The experiment was conducted at a temperature ranging from 800oC and 1000oC. XRD analysis was applied to observe phase transformation. For the kinetic study, two models, namely (1) Jander and (2) Ginstling-Brounhstein diffusion model, were applied. The mineral phase results indicated that both reductants yield Magnetite from Goethite in the laterite. The best fit model is obtained by the Jander model with the energy activation of 33.68 kJ/mol for anthracite reductant and 10.99 – 18.19 kJ/mol for palm kernel shell reductant, indicating that reduction is easier to occur using palm kernel shell.

Biogas has emerged as a promising alternative to gasoline due to the depletion of fossil energy and environmental concerns. An investigation was conducted to study the technical feasibility of an adsorbed natural gas (ANG) storage system using petung bamboo-activated carbons. The activated carbons were prepared by microwave-assisted pyrolysis (MAP) and a hybrid heating system for comparison. Microwave-assisted pyrolysis is a promising alternative technology for biochar production because it has several advantages over conventional pyrolysis such as uniform heating temperature, lower energy consumption, and uniform pore size. The characteristics of the obtained activated carbons were evaluated by scanning electron microscope (SEM) and Fourier transform infrared spectroscopy. The results showed that the higher power led to the shorter pyrolysis time. However, at a certain point, the higher power causes the biomass is not degraded completely. In this case, a microwave oven with 2 magnetrons produces a better heating temperature profile than the use of 1 magnetron. The character of activated carbon prepared using 70% power output (1120 W) is better than activated carbon prepared using 60% power output (960 W). In this condition, the pore size is more uniform and the number of functional groups is less. This implies that the petung bamboo activated carbon is the ideal candidate for ANG storage.

Twitter is one of the popular microblogs that allow users to write posts. Retweeting is one of the mechanisms for the diffusion of information on Twitter. One way to understand the spread of information is to learn about retweet predictions. This study focuses on predicting retweets using Evolutionary Undersampling Boosting (EUSBoost) based on user, content, and time-based features. We also consider the vector of text as a predictive feature. Models with EUSBoost are able to outperform models using the AdaBoost method. The evaluation results show that the best model can achieve an AUC performance score of 77.21% and a GM score of 77.18%. While the Adaboost-based models achieved AUC scores ranging from 68% to 69% and GM scores ranging from 62% to 63%. In addition, we found that there was no significant difference between using numeric features only and combining numeric and text features.

This study aims to determine the effectiveness of the addition of natural feed additives on the production performance and quality of broilers. The sample used in this study was DOC (Day Old Chicken) Cobb strain with the trademark CP 707 as many as 75 heads. The method used was experimentally designed using a completely randomized design with three treatments and five replicates using five broilers per replicate. The treatments were T0 = basal feed, T1 = basal feed with 0.5% natural feed additive, and T2 = basal feed with 1.0% natural feed additive. The variables used in this study include villous length, number of villi, and depth of villous crypts. Data were analyzed with ANOVA and continued with Duncan’s multiple range test. The results showed that the test of villi characteristics using combination of probiotics-phytobiotics-acidifier microencapsulation gave a significantly different effect (P

This work studies the leaching kinetics of nickel laterite in a citric acid solution. A new kinetics model that considers a reversible chemical reaction and internal diffusion of a product is proposed. The experiment was conducted at various temperatures (303, 333, and 358 K) and particle sizes (< 70 to 250 ?m). Whereas acid concentration, pulp density, and leaching time were constant at 0.1 M, 20% w/v, and 120 min, respectively. The experimental results showed that the leaching process was dependent on temperature and particle size. In the case of Ni, Al, and Fe leachings, the formation of complex molecules might lead to a steric hindrance of product diffusion; however, this was not observable for Mg. The proposed model was found to be much better than the conventional shrinking core models (SCM). Using the proposed model, the activation energy for nickel was found to be 121.38 ± 0.0324 kJ/mol, 78.98 ± 0.4157 kJ/mol, 1,022.62 ± 9.6507 J/mol for forward reaction, backward reaction, and diffusion, respectively.

The development of battery technology is the driving force behind the increasing demand for lithium, which has resulted in a decreased supply of lithium in the market and continues to be a challenge for the industry. In response to these conditions, the development of lithium recovery technology continues, and there is a search for sources of lithium that are easier to recover. One source of lithium that has the potential to be processed is geothermal brine using forward osmosis technology. The aim of this study was to determine the best operating conditions for forward osmosis as a substitute for conventional evaporation methods. The parameters to be optimized included pH and operating temperature. The flow rate in the forward osmosis process was controlled by two litres per hour (LPH), while the concentration of the draw solution was 6M. The operating temperature variations used were 40oC, 35oC, and 30oC, while the pH variations used were 7, 6, and 5. The best results were achieved at a pH of 5 with a temperature of 40oC. Apart from these operating conditions, the activity model (the Pitzer equation) showed superior results compared to the simple model (the Van’t Hoff equation), explaining the forward osmosis phenomenon.

As one of the hazardous and toxic solid wastes, spent catalysts need to be treated before the waste is discharged into the environment. One of the substances that need to be removed from the spent catalysts is the heavy metal ions and/or compounds contained therein. The method that can be applied is the extraction method using an acid solvent. In this study, the extraction process was carried out on spent catalysts samples from PT. Petrokimia Gresik. The focus of the study is on nickel extraction by varying the temperature in the range of 30–85 oC. A 1 M hydrochloric acid (HCl) solution was used as a solvent while the extraction process was 120 minutes. The experimental results show that the maximum nickel recovery of 14.70% can be achieved at a temperature of 85 oC. Kinetic studies were carried out using two kinetic models. The results of both models evaluation on the research data show that the lump model gives better results than the shrinking core model. The average error percentage of the lump model is smaller than the shrinking core model. It indicates that the extraction process was controlled by the diffusion step through the ash layer in the solid and chemical reactions simultaneously.

Kondisi pandemi membuat mahasiswa untuk beradaptasi pada kondisi pembelajarannya yang bersifat daring. Salah satunya adalah presentasi online. Public speaking dianggap sebagai salah satu keterampilan utama yang harus diperhatikan pada saat melakukan presentasi online. Tantangan yang dimiliki mahasiswa adalah membangun self eficacy untuk berbicara didepan umum. Kondisi dimana jika tidak teratasi dapat menimbulkan kecemasan dan tidak efektifnya presentasi. Untuk dapat mengoptimalkan kemampuan mahasiswa dalam public speaking terutama ketika presentasi secara online diperlukan upaya untuk meningkatkan efikasinya tersebut. Penelitian ini mengusulkan sebuah pelatihan yang disebut dengan Kelas Online PSOP (Public Speaking on Online Presentation). Pelatihan ini merupakan modifikasi dari modul yang dikembangkan oleh Toatmaster (2015). Pendekatan belajar yang dilakukan dalam pelatihan ini adalah pendekatan belajar experiential learning. Modul ini dilakukan tahapan validasi melalui expert judgement sebanyak 3 orang dan teruji valid secara isi. Selanjutnya dilakukan tahapan eksperimen dengan desain eksperimen one group pretest and posttest only. Penelitian ini menemukan sebanyak 98 orang siswa berkategori sedang dan 19 orang siswa memiliki kategori rendah, dan 11 orang dengan kategori tinggi. Subjek dalam penelitian ini berjumlah 14 orang mahasiswa dengan kategori self eficacy yang rendah. Penelitian ini membutikan bahwa Program Kelas online PSOP terbukti dapat meningkatkan self eficacy mahasiswa dalam melakukan public speaking secara online.

Basicity is an important parameter in the smelting of nickel laterite to obtain low-temperature melting point and low-liquidus slag viscosity, resulting in less energy consumption and a more effective smelting process ferronickel production. Nevertheless, it is still less studied in selective reduction of nickel laterite. In this work, the effect of binary, ternary, and quaternary basicity limonitic nickel ore had been investigated clearly to reveal the appropriate basicity in the selective reduction process. The basicity was modified with the addition of CaO, MgO, SiO2, and Al2O3 in nickel laterite. The reduction process was conducted in a muffle furnace at 1150 °C for 60 min. It was continued with the magnetic separation process to separate concentrate and tailing. The appropriate basicity type in selective reduction of limonitic ore was 0.3 of ternary basicity (BT1) and 0.2 of quaternary basicity (BQ1), which had a similar nickel grade and recovery, i.e., 6.08% and 88.33%, respectively. At low basicity, the addition of CaO and SiO2 could suppress the metallization of iron through troilite and fayalite formation, respectively. Nevertheless, more CaO addition at high basicity could inhibit the ferronickel agglomeration due to the formation of high melting point structures, i.e., melilite. Modifying basicity with the addition of MgO and Al2O3 resulted in a negative effect in selective reduction due to the formation of a complex structure of forsterite and magnesioferrite (with an aluminum substitute), which was more difficult to reduce than magnetite.

During the COVID-19 pandemic, teaching and learning activities have been shifted to online learning. Therefore, online discussion activities were carried out to achieve learning objectives. The transition of learning methods was expected to be able to replace face-to-face teaching and learning activities in schools. This research aimed to find out the reflection on the problems and how to solve the problems in online discussion activities by EFL Student-Teachers. The method used in this research is qualitative with narrative as the research design. Providing a questionnaire and interview that must be answered by EFL Student-Teachers. The participants of this research were 26 EFL Student-Teachers from one of the University in Cirebon who have carried out PLP II activities. The results of this research indicated that online discussion activities required good media and preparation for teaching and learning activities. EFL Student-Teachers were required to be creative in carried online discussion activities to get students' attention, and EFL Student-Teachers must be able to solve the problem faced during the online discussion as the reflection of teaching and learning activities. Keywords: Reflective Practice, Online Discussion, EFL Student-Teachers, COVID-19.

A study on mineral characterization and nano titanium dioxide synthesis from ilmenite ore of Bangka Island, Indonesia, has been carried out using a caustic fusion method and hydrochloric acid leaching. Comprehensive mineral characterization was conducted using X-ray fluorescence spectroscopy (XRF) and X-ray diffraction (XRD) to depict each fractionated particle's elemental composition and mineralogy, i.e., +80, ?80+100, ?100+150, ?150+200, -200+325, and -325 mesh. Other analyses performed are VSM to measure the magnetic properties and SEM to determine the distribution of elements at each particle size. Based on the characteristics of the ilmenite ore, magnetic separation was applied for the initial stage and analyzed gravimetrically. Later processing was the synthesis of nano titanium dioxide, conducted sequentially, including roasting and leaching. Roasting was run at 900°C with and without caustic soda, and then hydrochloric acid was applied. In reference to the elemental analysis, titanium (Ti) concentration is higher in smaller particle sizes and vice versa for iron (Fe) concentration, so the synthesis of nano titanium dioxide was carried out using a -100+150 mesh particle size. The optimum condition for nano titanium dioxide synthesis was 2:1 of NaOH and ilmenite weight ratio, 20% HCl concentration, and 4 hours of leaching time. The nano titanium dioxide (TiO2) obtained was then characterized using XRF, XRD, particle size analyzer (PSA), and transmission electron microscopy (TEM). Roasting with caustic soda showed better nano titanium dioxide purity with 96.04% of TiO2 with particle size in the range of 50–80 nanometers.

Cancer is one of the second deadliest diseases in the world after heart disease. Citing from the WHO's report on cancer, in 2018 there were around 18.1 million cases of cancer in the world with a total of 9.6 million deaths. Now that bioinformatics technology is growing and based on WHO’s report on cancer, an early detection is needed where bioinformatics technology can be used to diagnose cancer and to help to reduce the number of deaths from cancer by immediately treating the person. Microarray DNA data as one of the bioinformatics technology is becoming popular for use in the analysis and diagnosis of cancer in the medical world. Microarray DNA data has a very large number of genes, so a dimensional reduction method is needed to reduce the use of features for the classification process by selecting the most influential features. After the most influential features are selected, these features are going to be used for the classification and predict whether a person has cancer or not. In this research, hybridization is carried out by combining Information Gain as a filtering method and Genetic Algorithm as a wrapping method to reduce dimensions, and lastly FLNN as a classification method. The test results get colon cancer data to get the highest accuracy value of 90.26%, breast cancer by 85.63%, lung cancer and ovarian cancer by 100%, and prostate cancer by 94.10%.

Hubungan interpersonal saat ini membuat kekhawatiran tersendiri bagi masyarakat, karena remaja sering terjerumus dalam perbuatan yang dapat melanggar batas-batas nilai yang mengarah kepada perilaku seksual pranikah. Terjadi peningkatan perilaku seksual pranikah pada remaja Aceh. Banyak remaja yang berpacaran di bawah usia 15 tahun atau disebut dengan early starter, sehingga rentan terjadi perilaku seksual pranikah. Remaja yang masa berpacaran terlalu muda dapat mudah melakukan perilaku seksual pranikah. Salah satu cara menghindari perilaku seksual pranikah adalah dengan kontrol diri. Kontrol diri terdiri dari tiga aspek yaitu kontrol kognitif, kontrol perilaku dan mengontrol keputusan. Penelitian ini bertujuan untuk mendapatkan gambaran kontrol diri dalam mencegah perilaku seksual pranikah. Metode penelitian yang digunakan ialah metode kuantitatif dengan analisis deskriptif. Data diperoleh melalui kuisioner “kontrol Diri Terhadap Perilaku Seksual pranikahâ€. Subjek dalam penelitian ini berjumlah 290 orang siswa yang diperoleh berdasarkan metode cluster random sampling yang sesuai dengan karakeristik dan dianggap mewakili siswa Sekolah Menengah Pertama di Kota Lhokseumawe. Hasil penelitian menunjukkan bahwa sebagaian besar siswa Sekolah Menengah Pertama di Kota Lhokseumawe memiliki kontrol diri yang rendah (62%), artinya sebagian besar siswa Sekolah Menengah Pertama di Kota Lhokseumawe belum mampu mengatur dirinya untuk tidak melakukan perilakunya dalam mencegah perilaku seksual pranikah.

Sex education should be given from an early age to prevent sexual harassment. Giving sex education to children is an effort to provide information about the function of the private parts. It makes them aware of sex and sexuality and the importance of taking them as privacy. It is also an opportunity to instill moral values and ethics. This community service employed a Service-Learning approach by utilizing adapted learning methods as well as adequate facilitators. In this program, sex education is given to grade 1 (as an early introduction) and grade 6 students (as they are approaching pre-puberty) at a primary school with material related to everyday life. This program ran for two weeks and received a satisfying response from the students and the school stakeholders. The result shows that the students understood the material very well. In addition, there is a reasonably positive behavior change in the students' awareness to take care of themselves in association with their classmates, especially those related to their private parts.

Selama masa pandemi sekolah mengubah pola pembelajaran konvensional berbasis tatap muka menjadi pembelajaran jarak jauh (PJJ) yang sangat mengandalkan teknologi. Perubahan ini akhirnya menimbulkan beberapa dampak bagi generasi Z yaitu belum menyeluruhnya akses pembelajaran secara online, siswa belum terbiasa dengan budaya belajar jarak jauh, siswa selama ini terbiasa berinteraksi dengan teman-teman dan para guru secara langsung disekolah. Jika jika Covid-19 ini tidak segera berakhir dampak-dampak tersebut akhirnya akan menimbulkan kecemasan, frustrasi dan angka putus sekolah yang tinggi (Unicef, 2020). Kecemasan tersebut akhirnya akan mempengaruhi proses pembelajaran generasi Z salah satunya adalah kecemasan dalam berbicara di depan publik (Aryadillah, 2017). Untuk mengatasi hal ini penulis membuat suatu pengabdian masyarakat dengan memberikan program pelatihan public speaking yang bertujuan agar para siswa lebih percaya diri ketika berbicara di depan umum. Metode yang dilakukan adalah dengan melakukan perencanaan, persiapan, pelaksanaan dan evaluasi. Hasil dari pengabdian ini menyatakan bahwa ada perubahan yang terjadi pada peserta, beberapa siswa dapat memberikan intonasi yang tepat dalam menyempaikan informasi. Setelah proram pengabdian ini dijalankan memperoleh hasil bahwa peserta mendapatkan manfaat untuk menambah skill saat public speaking. Kemudian terdapat perubahan dalam hal percaya dirisehingga peserta dapat lebih termotivasi untuk berbicara di depan umum setelah mengikuti program pelatihan public speaking.

Geothermal silica is a potential source of amorphous silica for producing geopolymer concrete. The valorization of geothermal silica as a geopolymer concrete provides an opportunity for an added value to the geothermal-based power industry. In this study, silica content, NaOH molarity, and curing temperature effect were investigated and optimized for compressive strength using response surface methodology. The effect of the single parameter on geopolymerization was qualitatively observed using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy-coupled with energy dispersive X-ray spectroscopy (SEM-EDS). The characterization of the geopolymer samples using FTIR and SEM-EDS revealed that the aluminosilicate structure was formed in all geopolymer samples. The geopolymerization rate can be accelerated using the lower level of geothermal silica and the high level of NaOH molarity and curing temperature. Based on optimization studies, the R-square value was 99.89%. The optimum formulation was found at a silica content of 130 g, NaOH molarity of 10 M, and curing temperature of 80°C with a desirability value of 0.99. At the optimum condition, the compressive strength was calculated as 7.73 MPa.

Cancer is one of the deadliest diseases in the world with a mortality rate of 57,3% in 2018 in Asia. Therefore, early diagnosis is needed to avoid an increase in mortality caused by cancer. As machine learning develops, cancer gene data can be processed using microarrays for early detection of cancer outbreaks. But the problem that microarray has is the number of attributes that are so numerous that it is necessary to do dimensional reduction. To overcome these problems, this study used dimensions reduction Discrete Wavelet Transform (DWT) with Classification and Regression Tree (CART) and Random Forest (RF) as classification method. The purpose of using these two classification methods is to find out which classification method produces the best performance when combined with the DWT dimension reduction. This research use five microarray data, namely Colon Tumors, Breast Cancer, Lung Cancer, Prostate Tumors and Ovarian Cancer from Kent-Ridge Biomedical Dataset. The best accuracy obtained in this study for breast cancer data were 76,92% with CART-DWT, Colon Tumors 90,1% with RF-DWT, lung cancer 100% with RF-DWT, prostate tumors 95,49% with RF-DWT, and ovarian cancer 100% with RF-DWT. From these results it can be concluded that RF-DWT is better than CART-DWT.

This study aims to develop listening learning multimedia based on metacognitive strategies for intermediate BIPA students and to describe the feasibility of these products based on the validation of material experts and media experts. This research is a development research with a modification of the Borg & Gall development model, which includes the stages of information collecting, product development planning, product development, and product evaluation. The research instruments used are interview guides, needs analysis questionnaires, and product feasibility questionnaires. Data collection techniques employed are interviews and questionnaires. Descriptive statistics is used to analyze the product feasibility. The results of this study show that (1) the creation of listening learning multimedia based on metacognitive strategies are feasible for intermediate level BIPA learners, (2) based on material expert judgment, learning multimedia obtained a score of 4.58 out of a scale of 5 with the category of “very good”, while based on assessment of media experts, learning multimedia obtained a score of 4.45 from a scale of 5 with the category “very good”. Based on these findings, this learning multimedia can be used as an alternative of learning media for listening in the intermediate level of BIPA.

Cancer is one of the deadliest diseases in the world that needs to be handled as early as possible. One of the methods to detect the presence of cancer cells early on is by using microarray data. Microarray data can store human gene expression and use it to classify cancer cells. But one of the challenges of using microarray is its vast number of features, not proportional to its small number of samples. To resolve that problem, dimensionality reduction is needed to reduce the number of features stored in microarray data. Binary Particle Swarm Optimization (BPSO) is one of the methods to reduce dimensionality of microarray data that can increase classification performance. Although when combined with Backpropagation, BPSO still shows a relatively low performance. In this research, Modified Backpropagation with Conjugate Gradient is used to classify data that has been reduced with BPSO. The average accuracy result of BPSO+CGBP is 86.1%, giving it an improvement compared to BPSO+BP which averaged to 80.8%.

Hadith is the second source of law for Muslims after the Qur'an which comes from various forms of the words, actions and stipulations of the Prophet Muhammad or referred to as his sunnah. In order to make it easier for Muslims to apply the teachings of the hadiths, a classification system is needed that can categorize a hadith into a class or a combination of two of the three classes which called a multi-label classification. In building a text classification system, there are various classification techniques, one of which is k-Nearest Neighbor (KNN). KNN is a simple and effective classification method for text classification, but has a weakness in processing data with high vector dimensions so that the computation time is higher and the efficiency of text classification is very low. Mutual Information (MI) is used as a feature selection method to reduce vector dimensions because it has the ability to show how strong a feature is in making a correct prediction of a class. In this study Problem Transformation Method with the Binary Relevance (BR) approach is used so that the multi label classification process can be accomplished. The optimum results obtained in this study shows the value of hamming loss is 0.0886 or about 91.14% of data were correctly classified and computational time for 595 seconds by using MI as a feature selection, but without stemming.

Wordnet is a collection of words that interpret or present a meaning, in its development Wordnet has an important part, the Synonym Set or Synset. In making Synonym sets, synonyms are needed and the commutative nature of words is needed. To get word synonyms, the English language thesaurus becomes the reference data for taking synonym data. Broadly speaking, the difference between Wordnet and the dictionary is that the meaning of the word is related to other words, to determine the equation requires a commutative process. The process is made easy by using commutative methods that will produce a candidate synonym set. Candidates for the synonym set cannot be used for word syntax, the grouping process of words which produces the Synonym set as the final result must be carried out. The process of grouping words can one of them use clustering techniques, in this study will use Agglomerative Clustering techniques. In the process of agglomerative clustering techniques there is a threshold value to determine the number of repetitions or as a condition to stop the iteration process. The clustering process in this study will use a threshold value of 0.1 to 1 to test the best threshold value to produce the best Synonym set and calculate its accuracy value. Accuracy calculation and evaluation will use the F-measure method to find the best results.

On the development of Indonesian WordNet, the synonym set is an important part that represents the similarity of meaning between words. Synonym sets are built using the Indonesian Thesaurus as the lexical database. After going through the extraction process from the Indonesian Thesaurus, we will get a synonym set that has a similarity or word sense between words. In general, the difference between WordNet and the dictionary is their main focus, in which the dictionary usually focuses on just one word, while in WordNet the focus is on the meaning of words and connectedness with other words. Explained in previous research, the constructions of synonym sets were done using several approaches, which is clustering to produce synonym sets and WSD (Word Sense Disambiguation). In this article, the approach used to produce synonym sets is the ROCK (Robust Clustering Using Links) algorithm, which uses similarity and link values. The resulting synonym sets will then be used for lexical database development. Therefore, the main focus of this article is to produce synonym sets through the clustering process and calculate their accuracy, using the F-Measure method involving the gold standard for performance calculation and evaluation.

There is a shift from internal combustion engines to electric vehicles (EVs), with the primary goal of reducing CO2 emissions from road transport. Battery technology is at the heart of this transition as it is vital to hybrid and fully electric vehicles’ performance, affordability, and reliability. However, it is not abundant in nature. Lithium has many uses, one of which is heat transfer applications; synthesized as an alloying agent for batteries, glass, and ceramics, it therefore has a high demand on the global market. Lithium can be attained by extraction from other natural resources in igneous rocks, in the waters of mineral springs, and geothermal brine. During the research, geothermal brine was used because, from the technological point of view, geothermal brine contains higher lithium content than other resources such as seawater. The nanofiltration separation process was operated using various solutions of pH 5, 7, and 10 at high pressures. The varying pressures are 11, 13, and 15 bar. The nanofiltration method was used as the separation process. High pressure of inert nitrogen gas was used to supply the driving force to separate lithium from other ions and elements in the sample. The research results supported the selected parameters where higher pressure and pH provided more significant lithium recovery but were limited by concentration polarization. The optimal operating conditions for lithium recovery in this research were obtained at a pH of 10 under a pressure of 15 bar, with the highest lithium recovery reaching more than 75%.

The use of detergent predictably causes large quantities of phosphate ion in water bodies. It is considered to trigger eutrophication, that creates a severe reduction in water quality. Adsorption using activated carbon is one of the effective methods for the removal of phosphate from wastewater. Recently, the use of microwave irradiation in activated carbon preparation is a promising alternative to replace conventional heating using a furnace. In this study, the use of microwave heating was compared to conventional heating. The result showed that pore of activated carbon was larger than that of the char and the activated carbon prepared using 30% of ZnCl2 had the adsorption performance higher than that of prepared using 20% of ZnCl2. The optimum adsorption occurred at pH 4 and the equilibrium was reached after 180 minutes. The Langmuir equilibrium model was more appropriate than the Freundlich equilibrium model. While the kinetics model analyzed using pseudo-first-order, pseudo-second-order, internal diffusion, and external diffusion indicated that the pseudo second order was most suitable for the adsorption of phosphate by teak leaf activated carbon.

Given the low-cost and eco-friendly method, biotechnology has been widely utilized in industries as an alternative for physical and chemical processes, including in the biomining process (e.g., bioflotation and biobeneficiation). However, the use of biochemical reagent, which is selective for certain minerals, has not been well studied. This research was aimed to investigate the potential use of biosurfactant-producing mixotrophic bacteria as an alternative to chemical reagents during bioflotation and biobeneficiation process. Thirteen bacterial strains were investigated for their ability to produce biosurfactants and their effects on the surface properties of pyrite minerals. Bacteria-pyrite interaction experimental results showed that pyrite surface properties became more hydrophilic in the experimental systems inoculated with bacteria adapted with pyrite for 48 h than that without bacterial adaptation to pyrite, which was evidenced by the decrease in the contact angle of pyrite minerals by up to 50%. This evidence was also confirmed by the highest emulsifying index value (51.6%) attained during the bacteria-pyrite interaction. Hence, these bacteria can potentially be applied to selective flotation as pyrite depressants.

ZnO nanoparticle was synthesized by a simple hydrometallurgical method using raw material of electric arc furnace dust (EAFD),which is a solid waste in the stainless steel industry. Electric arc furnace dust contains 68.81% Zn in the form of zincite (ZnO) and simonkolleite (H10Cl2O9Zn5). The synthesis was carried out in two main steps, i.e., leaching and alkaline precipitation. In this study, the effect of leaching reagent, leaching temperature, and leaching reagent concentration on the percent extraction of Zn in the leaching process from electric arc furnace dust and the characteristics of the resulting ZnO product were studied. The experimental results showed that leaching reagent of acetic acid gives the highest percent extraction of Zn. The results also showed that the increase of temperature and acid concentration could improve the Zn extraction percentage. At 2M acid concentration, Zn extraction percentage already achieved 100%; hence the process is independent of temperature. The ZnO product has a purity of 96%. The XRD data confirmed the nano sizes of the ZnO product. A B S T R A K ZnO nanopartikel disintesis dengan metode hidrometalurgi sederhana menggunakan bahan baku berupa debu tungku busur listrik yang merupakan limbah padat industri baja tahan karat. Debu busur listrik mengandung 68,81% Zn dalam bentuk zincite (ZnO) dan simonkolleite (H10Cl2O9Zn5). Proses sintesis dilakukan dalam dua tahap utama yaitu pelindian dan pengendapan alkali. Pada penelitian ini dipelajari pengaruh reagen pelindian, suhu pelindian, dan konsentrasi reagen pelindian pada proses pelindian terhadap persen ekstraksi Zn dari debu tungku busur listrik dan karakteristik produk ZnO yang dihasilkan. Hasil percobaan menunjukkan bahwa asam asetat adalah reagen pelindian yang memberikan persen ekstraksi Zn tertinggi. Hasil percobaan juga menunjukkan bahwa semakin tinggi suhu dan konsentrasi asam yang digunakan, maka semakin meningkat persen ekstraksi Zn yang diperoleh. Tetapi pada konsentrasi asam 2M, suhu pelindian tidak terlalu berpengaruh karena dengan konsentrasi asam asetat 2M pada semua kondisi suhu pelindian, persen ekstraksi Zn yang diperoleh adalah 100%. Hasil pelindian menggunakan asam asetat pada kondisi optimum menghasilkan produk ZnO dengan kemurnian sekitar 96%. Data XRD juga menunjukkan bahwa ZnO yang terbentuk memiliki ukuran nano.

The study of geopolymers has become an interesting concern for many scientists, especially in the infrastructure sector, due to having inherently environmentally friendly properties and fewer energy requirements in production processes. Geopolymer attracts many scientists to develop practical synthesis methods, useful in industrial-scale applications as supplementary material for concrete. This study investigates the geopolymerization of fly ash and geothermal silica-based dry activator. The dry activator was synthesized between NaOH and silica geothermal sludge through the calcination process. Then, the geopolymer mortar was produced by mixing the fly ash and dry activator with a 4:1 (wt./wt.) ratio. After mixing homogeneously and forming a paste, the casted paste moved on to the drying process, with temperature variations of 30, 60, and 90 °C and curing times of 1, 3, 5, 7, 14, 21, 28 days. The compressive strength test was carried out at each curing time to determine the geopolymer’s strength evolution and simulate the reaction’s kinetics. In addition, ATR-FTIR spectroscopy was also used to observe aluminosilicate bonds’ formation. The higher the temperature, the higher the compressive strength value, reaching 22.7 MPa at 90 °C. A Third-order model was found to have the highest R2 value of 0.92, with the collision frequency and activation energy values of 1.1171 day−1 and 3.8336 kJ/mol, respectively. The utilization of coal fly ash and silica geothermal sludge as a dry activator is, indeed, an approach to realize the circular economy in electrical power generations.

Synthesis of activated carbon from coconut shell waste with ZnCl2 activation using microwave heating have been carried out. Coconut shell consists of 36.51% lignin, 33.61% cellulose and 19.27% hemicellulose which causes it can be used as a precursor in the synthesis of activated carbon. The activated carbon was further characterized using Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectrophotometer (FTIR) and NOVA Gas Sorption Analyzer-Quantachrome and used for the adsorption of methyl violet in aqueous solution with variation of pH, contact time and concentration of solution. The result showed that the pore of activated carbon was larger than that of the char. The optimum adsorption occurred at pH 3 and the equilibrium time was reached after 180 minutes. The Langmuir equilibrium model was more appropriate than the Freundlich equilibrium model. While the kinetics model analyzed using pseudo first order, pseudo second order, internal diffusion and external diffusion indicated that the pseudo second order was most suitable for the adsorption of methyl violet by coconut shell activated carbon.

Vinasse waste, which is a by-product of the alcohol industry, has polluted the rice field en- vironment in the Bekonang, Sukoharjo and surrounding villages. This problem arises into the realm of law with the publication of a law on alcohol which prohibits low-level alcohol producers to sell to the public. This regulation increasingly discourages alcoholic craftsmen who are mostly used as raw materials in herbal and medicinal industries. In addition to the narrower marketing, they are also confronted by farmers who are angered by the environmental pollution of vinasse waste that for decades has only been dumped into irrigation flows without treatment. Field observations and preliminary studies on vinasse waste content found no harmful ingredients to the environment ex- cept high acidity (4.5). The rest is the content of organic materials that can be utilized to fertilize the soil. Therefore waste alcohol should be processed with the addition of complementary organic materials to be used as a medium to grow probiotic bacteria that are very good for soil and plants. This activity is intended to provide education on how to process waste vinasse into liquid fermen- tation fertilizer that can be utilized by local residents and society in general. Activity method that will be done is socialization about potential waste vinasse, making waste processing equip- ment, giving skill to make liquid fermentation fertilizer and applying it to cassava plant land. These activities are expected to generate positive perception changes and increase knowl- edge of craftsmen and farmers in addressing vinasse waste issues. In addition, both parties are able to treat the harmful waste into probiotic bacteria and fertilizer products with high qual- ity. With this activity, the source of conflict of Bekonang village community will decrease slow- ly along with the socialization of the results of the activity to the wider community and the as- sistance of the village government as the administrative responsibility of Bekonang village

The disposal of synthetic dyes into the environment can cause water pollution. Methyl violet, a typical cationic dye widely applied in industries, can cause bad effect to the aquatic life due to its stability and biodegradability. It also reduces photosynthetic activity. In this study, modified Ceiba pentandra sawdust has been investigated as an adsorbent for the removal of methyl violet dye from aqueous solutions. The modification has been carried out using heating treatment at 110oC and 200oC for one hour. The FTIR spectra of raw and modified Ceiba pentandra sawdust were recorded using an FTIR technique (Perkin Elmer, USA) by the KBr pellet method. The spectrum was scanned in the range of 400 to 4000 cm-1 wavenumbers. The photomicrography of the exterior surface of raw and modified Ceiba pentandra sawdust was obtained by SEM (JEOL, Japan). Batch studies were performed to investigate various experimental parameters including pH, contact time, and initial concentration for the removal of this dye. The results show that heating treatment increases the amount of methyl violet adsorbed. Effective pH for methyl violet adsorption was 7. A greater percentage of dye was removed with a decrease in the initial concentration of dye. Quasi-equilibrium reached in 30 min. Equilibrium isotherms were analysed by Langmuir and Freundlich isotherm equations. Freundlich equation is found to best represent the equilibrium data for methyl violet-modified Ceiba pentandra sawdust system.

Salah satu masalah yang sering dihadapi oleh para petani, terutama petani sayuran adalah serangan hama yang dapat menggagalkan panen. Petani pada umumnya menggunakan pestisida kimia untuk membasmi hama tersebut karena pestisida kimia banyak dijual di pasaran dan sangat efektif dalam membasmi hama. Namun, penggunaan pestisida kimia, apalagi pada jangka waktu yang lama dan terus-menerus sangat berbahaya. Alternatif penggunaan pestisida organik yang jauh lebih ramah lingkungan dan tidak beracun merupakan solusi yang lebih baik untuk menggantikan peran pestisida kimia. Tujuan spesifik kegiatan pengabdian ini adalah memberikan pengetahuan yang memadai kepada petani sayur mengenai bahaya pestisida kimia dan kelebihan pestisida organik serta untuk mengembangkan potensi bahan-bahan alam sebagai bahan baku pembuatan pestisida organik sehingga dapat meningkatkan hasil panen dan nilai ekonomi sayuran. Hasil dari kegiatan pengabdian ini menunjukkan masyarakat sangat antusias untuk menggunakan pestisida organik sebagai pengganti pestisida kimia.

The increase of electrical industry using coal as an energy source resulting in accumulated solid waste such as fly ash.Coal fly ash is mainly composed of some oxides including Al2O3, SiO2 having active siteand unburned carbon as a mesopore material that anables it to act as a potentialadsorbent.However, the use of powder coal fly ash as an adsorbent is quite complex, especially in the filtration installation, so difficult to be applied in the industry.The aim of this study is to carry out granulation of the coal fly ash with the addition of carrageenan as a binder to improve the mechanical and chemical stability thereby increasing the effectiveness and efficiency of the adsorption process. Coal fly ash wasreacted with sodium hydroxide solution and then granulated with the addition of carrageenan 10, 15 and 20 w/w. Granular coal fly ash was further characterized its specific surface area, functional group and morphology. Furthermore, granular and powder treated coal fly ash were tested their adsorption ability for ion Pb (II). The results show that the addition of carrageenan as a binder can change the characteristics of coal fly ash, decrease specific surface area and adsorption capability. The adsorption of Pb (II) by coal fly ash granular follows the Langmuir isotherm model with a constant value of is 0.173 and KLis 0.329.