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Coal fly ash is generated in large quantities by coal-fired power plants and is commonly disposed of as waste despite containing reactive mineral phases. This study investigates the valorization of coal fly ash into a magnetic Fe₃O₄-decorated composite for Cu(II) removal from aqueous systems, linking waste reutilization with the development of low-cost and magnetically recoverable materials for water treatment. The composite was synthesized via a coprecipitation–thermal treatment route, promoting the deposition of iron oxide on chemically activated fly ash. The physicochemical properties of the resulting material were characterized using X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and N₂ adsorption–desorption (BET) analysis. Cu(II) concentrations before and after adsorption were quantified by atomic absorption spectroscopy (AAS). Batch adsorption experiments were performed under fixed experimental conditions to evaluate the influence of composite composition and contact time on Cu(II) removal. The Fe₃O₄-decorated fly ash composite exhibited enhanced magnetic recoverability and improved Cu(II) removal compared with non-magnetic fly ash, enabling efficient solid–liquid separation. Under the selected experimental conditions, approximately 80% Cu(II) removal was achieved, yielding an adsorption capacity of ~0.32 mg g⁻ 1 at an initial Cu(II) concentration of 4 mg L⁻ 1 and a contact time of 120 min. Kinetic analysis indicated that Cu(II) uptake followed pseudo-second-order behavior, suggesting chemisorption-controlled adsorption. The developed material is positioned as a low-cost, sustainable, and magnetically recoverable adsorbent for coal fly ash valorization rather than as a high-capacity adsorbent. The findings highlight the role of chemical activation and magnetic modification in tailoring fly ash-based composites and provide a basis for further performance optimization.

Indonesia has high biodiversity and is well-known for its medicinal plant diversity, which is both singular and globally affluent. Due to their secondary metabolite efficacy for various ailments; medicinal plants are commercially and highly useful to human. Secondary metabolites assure the plant from abiotic and biotic stressors and aid pollination and fruit distribution. However, the changing climate, deforestation, population growth, overharvesting and the unsustainable manner of medicinal plant collection for trade, may drive many populations extinct. The study aimed to review some climate change effects on Indonesian medicinal plants as potential medicine sources for discovery and human being development. By reviewing with emphasis how each of the individual factors affects the growth, development and plant secondary metabolites production. This review illustrates a common figure of environmental factors such as temperature, drought, and CO2 that affect Indonesia’s medicinal plants. It is evident that climate change is having a detrimental influence on existing resources’ life cycles, medicinal plant quality and production, habitat fragmentation, shifting distribution ranges, phenology pattern changes, etc. Compared to other commercial crops, medicinal plant research on climate change is infrequent and limited. The study suggests some different adaptive techniques be used to mitigate climatic challenges and preserve medicinal plants.

Argumentation skills are important for students to analyze and evaluate critical information, especially in complex science issues. Socio-Scientific Real-world Inquiry [SSRI] learning helps students develop deep scientific understanding and the ability to build evidence-based arguments in a real context. This study aimed to examine the effectiveness of SSRI learning model in improving argumentation skills. The research design used was quasi-experimental with a pretest-posttest non-equivalent control group design, in which argumentation skills were measured before and after the intervention in two groups: an experimental group consisting of 44 students who received learning with the SSRI model and a control group comprised of 46 students who followed the inquiry learning. Analysis of changes in pretest and posttest scores on each aspect of argumentation skills was conducted using a paired sample t-test. In contrast, comparison of posttest scores between the two groups was analyzed by independent sample t-test. Analysis of the effect size on each aspect of argumentation skills in the control group and experimental group using Cohen's Effect Size method. The analysis results showed that the SSRI learning model was more effective in improving argumentation skills than the inquiry learning. These results indicate that SSRI can be an effective learning approach for educators and educational policymakers in an effort to develop argumentation skills that are crucial for individuals.

This study aims to determine the comparison of the effect between the Numbered Heads Together (NHT) model equipped with Handout-AR and NHT model equipped with Microsoft PowerPoint on student learning activities on the buffer solution. The research sample was determined using the Cluster Random Sampling technique. The study data were obtained using documentation and observation techniques. The documentation technique was used to obtain data on the students’ midterm test results. The observation technique was used to obtain the data on the scores of student learning activities. The study data were analyzed using the Mann Whitney test. The results show that the application of the NHT model equipped with Handout-AR has a better effect on student learning activities on buffer solution material than the application of the NHT model equipped with Microsoft PowerPoint. These results are supported by the results of the Mann Whitney test and the average score of student learning activities from the two experimental classes. The data analysis using the Mann Whitney test produces asymp. Sig. 2-tailed value (0.000) greater than the significance level/a (0.050). The NHT/Handout-AR class has an average score of learning activities (87.6) which is greater than the NHT/Microsoft PowerPoint class (68.4).

One of the components of critical thinking is an explanation. This study aims to identify critical thinking skills in aspects of explanation using a performance assessment rubric. To measure students’ scientific explanations in chemistry learning, a performance assessment rubric is needed. The arrangement of rubrics based on indicators of students’ scientific explanations on chemical equilibrium material. This research uses the RASCH analysis model, the instrument was in good category. The number of samples is 122 students from one senior high school in Surakarta, Central Java, Indonesia. The results showed students still had difficulty explaining ideas, students had difficulty explaining phenomena and connecting with relevant information.

The purpose of this study was to see the results of the research analysis regarding the critical thinking of junior high school students through science lessons in Indonesia. This research was a systematic review of studies through the Scopus database. Search was done through nine stages with criteria at each predetermined stage, i.e.: stage I, initial search with the keywords “critical thinking” with the category “article title”; stage II, type of access “open access”; stage III, published in “2010 – 2018”; stage IV, “English” language; stage V, the type of source “journals and proceedings”; stage VI, keywords “critical thinking”; stage VII, “Indonesia” research location; stage VIII, field of study “Science”; and stage IX, “Junior High School” education level. Searching through these nine stages results in 13 articles. The focus of this study was to analyze critical thinking skills and the indicators used in these studies. Most studies reported that increasing the critical thinking skills of Junior High School students in Indonesia were still at a “moderate” level. This study recommends to do further research on experimentation-based learning with an environmental approach to enhance critical thinking skills.

Purpose This paper aims to examine the recipe for and standard methods of dyeing cotton fabric with natural dyes from jackfruit wood extract. The dyeing of the fabric was performed by immersion it without heating for a short time to obtain the best results. Design/methodology/approach The dyeing experiment using cotton fabric with jackfruit wood extract was conducted by immersion at room temperature. The independent variables studied were the mordant method, type of mordant, mordant concentration, salt concentration and dyeing pH. The dependent variables were colour strength and colour fastness to washing and rubbing. The orthogonal array L16 (45) was used in the study to obtain the optimal values for each parameter of the response variables. The multi-response signal-to-noise (MRSN) method was used to optimise the five response variables with different quality characteristics so that the best parameters could be obtained based on the highest MRSN ratio value. Findings The best parameters were obtained at an MRSN value of 4.5254 under A3B3C1D2E4 conditions, namely, the dyeing process with post mordant, aluminium nitrate type mordant, mordant concentration of 10 g/L, salt concentration of 15 g/L and dyeing a pH: of 10. Under these conditions, the value of K/S was obtained at 1.893, colour fastness to washing (GS: 4) and (SS: 4–5), dry rubbing (SS: 5) and wet rubbing (SS: 4–5). Research limitations/implications Obtaining a standard recipe and method for dyeing cotton cloth with jackfruit wood extract by immersion without heating is expected to lead to the development of natural dyes, and especially their application on an industrial scale. This standard and method can be used as technical guidelines by industry. The use of aluminum nitrate as a mordant will help achieve optimal dyeing results. The use of polyaluminium chloride (PAC) mordant, which has the potential to produce high colour strength, and papaya fruit sap, which has the capacity to increase colour fastness, still need to be developed to improve the results of natural dyes. Practical implications The standard recipe and dyeing method will be able to improve the results of the dyeing of cotton fabrics with natural dyes. Short immersion dyeing without heating and the optimal results obtained are the main attractions for their use by the textile/batik industry, as the process is easier and a lower cost. The results of dyeing with dark colours and good colour fastness mean the textile products are of the higher quality demanded by consumers, thereby increasing sales. This will encourage the use of and increase the need for natural dyes by industry, consequently reducing the use of synthetic dyes. Social implications The use of natural dyes, chemical mordant from aluminum salts, and natural mordant from papaya fruit sap in the dyeing process in the textile/batik industry in Indonesia will produce eco-textile and eco-batik products that are environmentally friendly and of high quality. This in turn will increase consumer interest and sales, meaning that the income and economy of workers in the textile industry/crafts sector will also increase. In addition, the use of natural dyes with the selection of a safe mordant (not containing heavy metals) will reduce the use of synthetic dyes, which pollute and damage the aquatic environment. Originality/value This study found a standard recipe and method of dyeing cotton fabric with natural dyes from jackfruit wood extracted by immersion without heating for a short time to obtain the best results. In addition, the discovery was of PAC, a new mordant which is effective in the use of natural dyes can give high colour strength to cotton fabric. In addition to the discovery of a new mordant, PAC, which has the potential to produce high colour strength, papaya fruit sap also has the capacity to increase colour fastness with the use of natural dyes from the flavonoid group.

Orthosiphon aristatus (Java Tea) is a traditional and economically valuable medicinal plant with different pharmaceutical activities for preventing various diseases. Air temperature is one of the environmental elements that have an impact on plant growth and herbal production. The study aimed to assess how java tea plants respond to high air temperatures and to learn if soil with compost fertilizer may have a substantial impact on plant growth. The research was arranged using a completely randomized design, with air temperature as the main factor with three replicates for each treatment. Plastic Pots of java tea plants were maintained in the greenhouse (control) for three months and in the growth chamber day/night temperatures of 25/25°C, 30/25°C, 35/25°C, 40/25°C, 45/25°C and 50/25°C. Plants placed in a growth chamber showed significantly affected by temperature by comparing treatments in the greenhouse (control). Java tea plants kept at 30/25°C and 35/25°C had considerably higher plant height, leaf numbers, fresh and dry weight values than other treatments, whereas the 40°C treatment had the greatest growth decline, reduced leaf number, dry weight, and fresh weight. Moreover, all plants subjected to 45/25°C and 50°C/25°C in the growth chamber suffered more severely in all traits up to mortality. Therefore,30/25°C treatment would be more valuable for high marketability due to increased plant height, leaf number, and dry mass compared to other treatments.

Advances in science and technology, mainly Information and Communication Technology (ICT), have a significant impact on the management of education today. It enables the development of an assessment system to facilitate the teaching and learning process. For this reason, there is a great need to develop assessment instruments. The purpose of this study is to validate the instrument of chemical literacy ability of Islamic high school students (Madrasah Aliyah) in Central Java in Indonesia. This instrument is in the form of chemical literacy questions in computer media (computer-based tests). Data needed to analyze the model quantitatively was obtained selectively from a sample of 67 respondents. Data validity and reliability were evaluated using the Rasch model. The findings show that Cronbach-α is 0.82 and reaches an acceptable PT-Measure range. Outfit Mean Square or Outfit Mean Square (MNSQ) and standard outfit z (ZSTD) values. It shows that the reliability of items was 0.95; the reliability of people was 0.82. Cronbach's Alpha (α) measures the interaction between respondents and items, and this value indicates that the instrument used is in perfect and practical condition with a high level of reliability so that it can use in actual research. Chemical literacy assessment results show that the ability of chemical literacy in Islamic high school students is still low, of the 67 respondents, the average ability of chemical literacy is 48.50.

Purpose>This paper aims to select a type of mordant from aluminium salts, namely, aluminium sulphate, aluminium nitrate and polyaluminium chloride (PAC) with the lowest potential for contamination so that their use will minimise pollution from natural dye waste. It also aims to determine the pollution value of natural dye immersion waste from jackfruit wood extract, secang wood, mangsi fruit and several synthetic dyes, to identify potential environmental pollution.Design/methodology/approach>Dyeing with natural dyes was performed by exhaust at room temperature by the pre-mordant method, while with synthetic dyes it was performed by exhaust according to the dyeing procedure (reactive, vat and naphthol). The groundwater, mordant solutions, natural dye extract and the waste-water from the natural and synthetic dyes were then tested to determine their biological oxygen demand (BOD5), chemical oxygen demand (COD), total suspended solids (TSS), pH, Al and heavy metal contents such as chromium (Cr), copper (Cu), cadmium (Cd), nickel (Ni), cobalt (Co) and lead (Pb).Findings>Aluminium sulphate had the lowest pollution load while PAC had the highest, as aluminium sulphate had a higher BOD5/COD ratio (0.62–0.67) than aluminium nitrate (0.56–0.64) or PAC (0.44–0.54). The dyeing waste from the three natural dyes contained an acidic pH of 3.5–4.2, Al of 75.280–621.34 mg/L, Cr of 0.154–0.215 mg/L and Cu of 0.035–0.072 mg/L. The values of TSS, COD and BOD5 are higher than the quality standards of the waste but are environmentally friendly because the ratio of the BOD5/COD values from the waste ranges from 0.44–0.67.Research limitations/implications>The findings indicate that as a mordant, aluminium sulphate results in lower pollution loads than aluminium nitrate and PAC. However, all three mordants contain Cr and Cu, albeit in negligible concentrations. Therefore, it is recommended that future studies strive to identify a mordant that has lower pollution loads and does not contain metals but can increase dyeing results to satisfy consumer requirements. It is the hope that, with the discovery of a new mordant, natural dyes will be the solution for the heavy metal pollution caused by synthetic dyes.Practical implications>The use of environmentally-friendly mordants and natural dyes in the Indonesian textile and batik industry will give rise to superior quality eco-textile and eco-batik products. Such environmentally-friendly and high-quality products will not only increase competition and consumer interest but increase product sales as well which will, in turn, increase incomes and the economy. Additionally, an increase in the use of natural dyes by the textile and batik industry will serve as additional income to the communities and farmers from which the raw materials for the natural dyes are sourced thereby creating jobs and increasing welfare.Social implications>As environmentally-friendly mordants and natural dyes replace the hazardous and toxic materials currently used in the textile and batik industry, it guarantees the health and safety of its consumers and workers. Furthermore, as the waste-water produced is biodegradable, it reduces river and groundwater pollution. It is, therefore, expected that this information will not only lead to a shift in attitude within the textile and batik industries but the adoption of environmentally-friendly materials, for the sake of the environment, as well as the development of eco-textile and eco-batik products.Originality/value>Aluminium sulphate is a mordant type of aluminium salt with a lower potential for contamination than aluminium nitrate and PAC. However, PAC has been discovered to be a mordant for natural dyes, as has the fruit of the mangsi shrub, which has recently been discovered as a naturally occurring blue dye.