Yeanchon Henry Dulanlebit

Heavy metal pollution in aquatic systems increases the need for sustainable and efficient natural adsorbent materials, and carrageenan extracted from Eucheuma cottonii, which contains O–H, S=O, C–O–S, and 3,6-anhydrogalactose functional groups, offers strong potential for binding metal ions. However, the adsorption efficiency of natural carrageenan for Copper (Cu2+) and Cadmium (Cd2+) ions remains limited, which frames the central problem of this study. In addressing this issue, the method employed involves synthesizing carrageenan hydrogel through alkaline extraction of Eucheuma cottonii and evaluating its adsorption capacity under controlled experimental conditions. The hydrogel was characterized and tested at pH 6–7, with a contact time of 90 minutes, an initial concentration of 200 mg/L, and an adsorbent mass of 6 g, followed by kinetic and isotherm modeling to analyze adsorption behavior. Based on the Findings, ionic exchange interactions between sulfate ester groups of K-carrageenan and metal cations significantly enhance adsorption performance, with the adsorption process following a pseudo-second-order kinetic model and the Freundlich isotherm providing the best fit R2 > 0.90, indicating heterogeneous multilayer adsorption. In the Conclusion, the chemically modified carrageenan hydrogel demonstrates effective adsorption of copper and cadmium ions and presents strong potential as an eco-friendly and efficient biomaterial for heavy metal remediation.

The ability to think creatively and critically is considered the main cognitive competency. This study aimed to measure the thinking ability of students (n = 33) who participated in a laboratory activity in analytical chemistry. Case study methods were used to collect qualitative data, which supports quantitative data. The student’s creative and critical thinking abilities are measured by correlating the test result with their observations and responses. The results show that the student’s creative and critical thinking abilities are qualified as sufficient. An average of 46.96% of the students could provide correct answers, with the highest percentage on mixture separation tasks (72.7%). The students also showed creative and critical thinking abilities in creating and defining the result after consideration, resolving problems, providing answers with sound reasoning, observing, creating combinations and objects, and detailed ideas regarding the task indicators. The students could also define terms, analyze questions, and adapt their approaches to resolve tasks. The abilities of some students to identify problems from several points of view are still considered low, and they need to be able to identify issues based on given pictures and assess topics from different perspectives. The laboratory activity should create more indicators to think critically and creatively about every aspect. Keywords: creative thinking, critical thinking, abilities of future teachers, analytical chemistry, laboratory activity

Seaweed is a carbohydrate polymer of alginate, agar, and carrageenan which can be extracted and purified as hydrocolloids. Each carbohydrate has different physicochemical properties and hydrocolloids can form gels when dispersed in water. To achieve targeted hydrocolloids according to specific purposes and functions, conventional extraction methods, and several green extraction methods for extracting seaweed have been proposed and discussed. The conventional extraction method is in the form of solvent extraction (SLE), while the green extraction includes: microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), supercritical fluid extraction (SFE), pressurized solvent extraction (PSE), and reactive extrusion which automatically selectively presented as a promising method for extracting hydrocolloids in seaweed. These methods have been applied by taking into account the recovery rate, time, volume, temperature, pH, ratio, and type of solvent, as well as the type of method. This study discusses extraction methods that can extract bioactive compounds from seaweed with high yields and are economical and environmentally friendly

Leachate is a liquid arising from the decomposition of waste that has decayed due to the flow of external water into the landfill. Leachate can be toxic. generally, leachate contains several high inorganic metals, including lead. Lead is one type of heavy metal that has a high toxicity. This study aims to determine the initial concentration of lead (Pb) in leachate and the percent efficiency of polyaluminium chloride (PAC) coagulant in reducing lead levels in IPST Toisapu, Ambon City. Lead content was analyzed by coagulation using an atomic absorption spechtrophotometer (AAS). Coagulation is a chemichal process used to remove particles that can cause environmental pollution. The coagulant used is a polyaluminium chloride coagulant. The results of the analysis showed that the initial lead concentration at IPST Toisapu was 2.7670mg/L and the percentage of PAC coagulant efficiency was 500, 600, 700, 800 and 1000 mg/L respectively 61,59%; 69,92%; 73,55%; 77,17% and 84,79%. The results showed that PAC coagulant was effective in reducing lead levels in leachate.

One of the leaves that can be consumed to fill nutritional need for people’s is kecipir leaves (Phosphocarpus tetragonolobus L). This leave contains minerals among them caloium, potassium and phosphorus but the level is calcium potassium and phosphorus at kecipir not yet know. Therefor this study was making conduoted to find out level of caloium, potassium and phosphorus in kecipir leave at two different location that is Urimesing village and Eti village. Calcium and potassium levels are analyzed SSA while phosphorus levels are analyzed UV-VIS analysis result indicate calcium, potassium, phosphorus level in kecipir leaves at urimeseng village is 904,25 mg/100g, is 100,46 mg/100g and calcium potassium, phosphorus levels in kecipir leave at Eti village is 1.162,59 mg/100g and 190,498 mg/100g. based on these result obtained calcium, potassium and phosphorus levels with different values from each sampling location. This happened because of geographic location, soil structure and water content greatly affect the levels of calcium, potassium, and phosphorus.