Hematite (α-Fe2O3) with uniform hexagonal flake morphology has been successfully synthesized using a combination of gelatin as natural template with F127 via hydrothermal method. The resulting hematite was investigated as adsorbent and photocatalyst for removal of ibuprofen as pharmaceutical waste. Hexagonal flake-like hematite was obtained following calcination at 500 °C with the average size was measured at 1–3 µm. Increasing the calcination temperature to 700 °C transformed the uniform hexagonal structure into cubic shape morphology. Hematite also showed high thermal stability with increasing the calcination temperatures; however, the surface area was reduced from 47 m2/g to 9 m2/g. FTIR analysis further confirmed the formation Fe-O-Fe bonds, and the main constituent elements of Fe and O were observed in EDX analysis for all samples. α-Fe2O3 samples have an average adsorption capacity of 55–25.5 mg/g at 12–22% of removal efficiency when used as adsorbent for ibuprofen. The adsorption capacity was reduced as the calcination temperatures increased due to the reduction of available surface area of the hexagonal flakes after transforming into cubes. Photocatalytic degradation of ibuprofen using hematite flakes achieved 50% removal efficiency; meanwhile, combination of adsorption and photocatalytic degradation further removed 80% of ibuprofen in water/hexane mixtures.
This research aims to analyze TPACK items using the Rasch model in terms of validity, reliability, item difficulty and bias items. The method used is descriptive quantitative with 34 pre-service chemistry teachers in semester VI consisting of 26 female students and 8 students from Sebelas Maret University (UNS). The instrument used in this study was the matter of Teachnological Pedagogical Content Knowledge (TPACK) which was adapted from the PPG Teachnological Pedagogical Content Knowledge (TPACK), which consisted of 30 multiple choice questions. The results showed that: 1) the validity of the suitability level of items was 27 questions that were fit and 3 questions that were not fit. 2) the results of raw variance data of 33.5% indicate that the requirements for Raw variance explained by measures of at least 20% can be met and the variance that cannot be explained by the instrument of 8.2% also meet the criteria ie, not to exceed 15%. 3) Reliability of pre-service chemistry teachers is 0.52 in the weak category, item reliability is 0.90 in the good category and reliability between pre-service chemistry teachers and items 0.64 in the sufficient category. 4) The level of difficulty of the questions is very difficult, difficult, easy, very easy and is dominated by questions that are categorized as difficult. 5) there are no questions that have a probability of less than 5% so there are no biased items. In conclusion, TPACK item analysis using the Rasch model is valid, reliable, item difficulty is very good and there are no biased items. So the questions that have been analyzed can be used to measure TPACK on pre-service chemistry teachers.
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