71 research outputs found
Sorption of Cd(II) and Pb(II) ions onto Shorea acuminata sawdust: Isotherm, kinetics and sorption mechanism studies
No full textThe potential of Shorea acuminata (also known as Dark Red Meranti) sawdust as a sorbent to clean-up metal contaminated water was investigated in a batch sorption system. Its efficacy was evaluated at different pH, contact time and initial metal concentration. Equilibrium isotherm data were best described using the Langmuir isotherm model, while the kinetics followed the pseudo-second-order model. The maximum sorption capacity (Q) of Dark Red Meranti sawdust, estimated from the Langmuir equation were 94 and 328 mg/g for Cd(II) and Pb(II), respectively. FTIR analysis confirmed that O- and N-containing functional groups are the main sorption sites in Dark Red Meranti sawdust
Razor clam (Ensis directus) shell as a low-cost adsorbent for the removal of Congo red and Rhodamine B dyes from aqueous solution
No full textActive biopolymer film based on carboxymethyl cellulose and ascorbic acid for food preservation
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Removal of methyl orange and methylene blue dyes from aqueous solution using lala clam (Orbicularia orbiculata) shell
No full textChitosans as soil amendments for the remediation of metal contaminated soil
No full textResearch was conducted to evaluate the potential of chitosan, a fishery waste-based material, and its derivative cross-linked chitosans, as soil amendments for the remediation of metal contaminated land. This research comprised modification of chitosan followed by a characterisation study, a batch sorption study, two pot experiments and a biodegradation study. Chitosan was modified with three cross-linking reagents, namely glutaraldehyde (GLA), epichlorohydrin (ECH) and ethylene glycol diglycidyl ether (EGDE). The characterisation study used X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and Fourier transform infrared spectroscopy (FTIR) methods to investigate the effect of cross-linking treatment on the surface and physical properties of chitosan, the effect of metal interaction on the surface properties of chitosan and cross-linked chitosans, and the binding mechanism(s) of metal ions onto the chitosans. Cross-linking treatments on chitosan enhanced its chemical stability in acidic media and increased its BET surface area. Metal interaction reduced the crystallinity and changed the surface morphology of the chitosans. FTIR analysis revealed that the complexation of metal ions was through dative covalent interaction with the amino and hydroxyl groups of the chitosans. The batch sorption study evaluated the ability of chitosan and cross-linked chitosans to bind heavy metals. The effects of contact time, initial metal concentration and background electrolyte on metal binding were assessed. The binding behaviour was described by several kinetic and isotherm models. The maximum binding capacity (Q) values, estimated using the Langmuir isotherm model for the chitosans were comparable with other low-cost sorbents reported in the literature. The sorption-desorption study showed that the chitosans were able to retain metal ions on their surfaces, even at dilution factor of x11. The pot experiments evaluated the effectiveness of chitosan and chitosan-GLA in immobilising heavy metals in the contaminated soil. Their effects on plant growth and metal accumulation in plant tissue were determined using Lolium perenne (perennial ryegrass) and Brassica napus (rapeseed). For perennial ryegrass, the results were dependent on the rate of addition of the chitosans. Low application rates (up to 1% w/w) resulted in an increase in metal uptake, whereas 10% (w/w) addition decreased metal uptake. For rapeseed, metal uptake was decreased at all rates of application of chitosans. The ammonium acetate extractable metals in soil decreased following application of chitosan and plant growth. The biodegradation study measured microbial breakdown of the chitosans in both non-contaminated and contaminated soils. It was estimated that a longer period is required to complete the breakdown of the cross-linked chitosans (up to approximately 100 years) than unmodified chitosan (up to approximately 10 years). The influence of biodegradation on the bioavailable fraction of heavy metals in soil was studied concurrent with the biodegradation trial. It was found that the binding behaviour of chitosan for heavy metals in soils was not affected by the biodegradation process
VLE of carbon dioxide loaded aqueous potassium lysinate with separate blends of piperazine and 2-amino-2-methyl-1-propanol
No full textIn this study, vapour-liquid equilibrium of carbon dioxide in aqueous potassium lysinate (LysK) with separate blends of piperazine (PZ) and 2-amino-2-methyl-1-propanol (AMP) were studied for a wide range of temperature (303.15 – 343.15K), pressure (450 – 4100kPa) and solvent concentration (1 – 3 molar). The effect of promoters such as AMP and PZ on the carbon dioxide absorption capacity of LysK was investigated. Results show that carbon dioxide loading capacity has an inverse relation with temperature and solution concentration and the highest loading takes place at highest pressure. Significantly, LysK-AMP gave a maximum CO2 loading value of 3.62 moles as compared to LysK-PZ of only 1.49 moles, both at highest pressure of approximately 4000kPa. Thus AMP is proven to be more effective promoter to enhance carbon dioxide absorption than PZ
Minat Karir Siswa di Bidang Sains: Studi Pembelajaran Berbasis STEM pada Topik Buffer
No full textThe modern era is currently highly dependent on technology in almost all aspects, so the demand for experts in the field of technology is increasing. However, this does not match the situation in schools. Therefore, countries in the world are starting to implement the STEM approach to the national curriculum. This study aims to determine the increased interest in a career in science for students after applying the STEM approach. This research is a quasi-experimental using pretest-post-test control group design. The instrument used scientific career interest questionnaire that refers to the Social Cognitive Career Theory. The results show that the application of STEM through STEM activities such as formulating problems, designing solutions, practicums, and planning projects, will provide knowledge about students\u27 career interests. The increase in students\u27 career interest in science in the material on buffer solutions shows significant results. Environmental aspects more dominantly influence students\u27 career interests with the dominant indicator being school teaching staff. Further research can be carried out to see the increase in students\u27 interest in careers in science after implementing a STEM approach at a larger sample level such as a sample of high school students in a city.Era modern saat ini sangat bergantung pada teknologi hampir di segala aspek, sehingga permintaan akan tenaga ahli di bidang teknologi semakin meningkat. Namun, hal ini tidak sesuai dengan keadaan di sekolah. Oleh karena itu, negara-negara di dunia mulai menerapkan pendekatan STEM ke dalam kurikulum nasional. Penelitian ini bertujuan untuk mengetahui peningkatan minat berkarir di bidang sains bagi siswa setelah menerapkan pendekatan STEM. Penelitian ini merupakan penelitian quasi eksperimen dengan menggunakan rancangan pretest-post test control group design. Instrumen yang digunakan adalah kuesioner minat karir sains yang mengacu pada Social Cognitive Career Theory. Hasil penelitian menunjukkan bahwa penerapan STEM melalui kegiatan STEM seperti merumuskan masalah, merancang solusi, praktikum, dan merencanakan proyek, akan memberikan pengetahuan tentang minat karir siswa. Minat karir siswa di bidang sains pada materi larutan penyangga menunjukkan berada pada kategori cukup. Aspek lingkungan lebih dominan mempengaruhi minat karir siswa dengan indikator yang dominan adalah tenaga pengajar sekolah. Penelitian lebih lanjut dapat dilakukan untuk melihat peningkatan minat siswa terhadap karir di bidang sains setelah menerapkan pendekatan STEM pada tingkat sampel yang lebih besar seperti sampel siswa SMA di kota
Systematic Literature Review: Opportunities and Strategies for Implementing Artificial Intelligence in Chemistry Learning in Indonesia
No full textThere are major changes in industrial structure where digitalization and technological innovation are becoming the main factors of economic growth.This research aims to identify opportunities and strategies in the application of artificial intelligence (AI) to enhance chemistry learning in Indonesia. Through the systematic literature review (SLR) method, this research reviews 33 journals related to the application of AI in education, particularly in the subject of chemistry. Analysis shows that AI has the potential to make a significant impact through a more personalized, interactive, and adaptive approach to student needs. In addition, AI offers solutions to learning challenges, such as limited laboratory infrastructure, through the use of virtual simulations that facilitate experimental practice. Strategies that support the implementation of AI in chemistry education in Indonesia include improving access to technology, continuous teacher training, and raising awareness of technological changes in education. With effective implementation, AI is expected to make a real contribution to improving the quality of chemistry education in Indonesi
Effect of Neodymium Ions on Density and Elastic Properties of Zinc Tellurite Glass Systems
No full textThe aim of this work is to determine the effect of Nd3+ ion concentration on the elastic properties of zinc-tellurite glass for the development of waveguide lasers. A series of Neodymium doped zinc-tellurite (NZT) glass system of composition [(TeO2) 0.70 (ZnO) 0.30] (1-x) Nd2O3 (x), x =0, 0.01, 0.02, 0.03, 0.04 and 0.05, were synthesized by using conventional melt-quenching method. XRD analysis confirmed the amorphous nature of the glass; the FTIR confirmed the presence of TeO3 and TeO4 in the glass network. The density of the glass system increases with increase in neodymium concentration. The longitudinal ultrasonic velocity decreases from 3737.01 to 3045.23 ± 10 ms−1, and the shear velocity decreases from 1959.31 to 1887.81 ± 10 ms−1. The experimental results have shown that the elastic properties depend on the composition of the glass systems and the effect of neodymium (Nd2O3) within the glass network.</jats:p
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