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Environmental Chemistry Modules Development to Enhance Students' Creative Thinking Abilities in Heavy Metal Water Pollution Materials Hadi Apriyoanda; Agus Sundaryono; M. Lutfi Firdaus
PendIPA Journal of Science Education Vol 4, No 1 (2020): NOVEMBER - FEBRUARY
Publisher : University of Bengkulu

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (311.635 KB) | DOI: 10.33369/pendipa.4.1.1-6

Abstract

Development of teaching material based on laboratory research is one way that can be done to improve students' creative thinking abilities in meeting the challenges of 21st century learning. The aims of this study are to determine the feasibility of the developed environmental chemistry modules, to improve of students' thinking abilities and determine the students’ responses to the use of modules in environmental chemistry lectures. Module development by R and D methods 4D model, namely Define, Design, Develop and Disseminate. Module quality is determined by expert validation test. Based on the results of expert validation, the module developed obtained 90.91% percentage of eligibility with a very good category. Based on the N-Gain value obtained, an increase in students' creative thinking abilities on the aspect of  flexibility was 0.47, and the aspect of elaboration was 0.64 with medium category. The student responses to the use of modules in learning enviromental chemistry obtained a percentage of 83.82% with very good category.
PEMANFAATAN ARANG AKTIF SABUT KELAPA SAWIT SEBAGAI ADSOBEN ZAT WARNA SINTETIS REACTIVE RED-120 DAN DIRECT GREEN -26 Melfi Puspita; M. Lutfi Firdaus; Nurhamidah Nurhamidah
ALOTROP Vol 1, No 1 (2017)
Publisher : University of Bengkulu

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33369/atp.v1i1.2727

Abstract

The problem of environmental polution caused by waste of batik industry lately is increasing, so it needed a method to overcome that problem. The aim of this study was to determine the ability of activated charcoal from coconut fiber palm in adsorbing Reactive Red-120 and Direct Green-26 dyes in waste of batik along with determining the parameters of isotherms adsorption using UV-Vis Spectrophotometer analysis method. Variations of pH, contact time, adsorbent weight and temperature were carried out as variable to obtain optimum conditions of the adsorption process. The optimum of conditions for Reactive Red-120  occured at pH 3 and a contact time of 30 minutes, while Direct Green-26  occurred at pH 4 and a contact time of 40 minutes, with each adsorbent weight 150 mg and the temperature 30 °C. Adsorption isotherms determined by Freundlich and Langmuir models with maximum adsorption capacity (Qmax) were obtained for the Reactive Red-120  was 400 mg/g, while Direct Green-26 is 169 mg/g. 
PENENTUAN KESETIMBANGAN, TERMODINAMIKA DAN KINETIKA ADSORPSI ARANG AKTIF TEMPURUNG KELAPA SAWIT PADA ZAT WARNA REACTIVE RED DAN DIRECT BLUE Rensy Aula Sari; M. Lutfi Firdaus; Rina Elvia
ALOTROP Vol 1, No 1 (2017)
Publisher : University of Bengkulu

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33369/atp.v1i1.2706

Abstract

This perpose of this research was to know the isotherm, kinetics and thermodynamics adsorption of synthetic  dye onto activated carcoal from palm oil shell. The synthetic dye were Reactive Red and Direct Blue. The model of isotherm were Langmuir and Freundlich, kinetics adsorption tested were Pseudo orde-1 and Pseudo orde-2, and also thermodynamics were free energy change (?Go), enthalpy change (?Ho), and entropy change (?So). The dominant isotherm adsorption was isotherm Freundlich, kinetic adsorption Pseudo 2 th order  with the value (?So), (?Go) and (?Ho), Reactive Red were 0,0028 Kj/mol.K , -3,93 Kj/mol, and -36,12 Kj/mol respectively. Whereas in direct blue were 0,0034 Kj/mol.K, -1,67 Kj/mol,and -30,16 Kj/mol respectively. 
PEMBUATAN NANOPARTIKEL PERAK (NPP) DENGAN BIOREDUKTOR EKSTRAK BUAH Muntingia calabura L UNTUK ANALISIS LOGAM MERKURI Purwo Ismaya Sari; M. Lutfi Firdaus; Rina Elvia
ALOTROP Vol 1, No 1 (2017)
Publisher : University of Bengkulu

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33369/atp.v1i1.2708

Abstract

The goal of this research was to make silver nanoparticles (NPP) with a cherry fruit extract bioreductor which was used for mercury metal analysis by using a digital image method. The process of making silver nanoparticles had done by a bottom up method involving a reduction reaction. The precursors used were 1 mM AgNO3 solution and as a bioreductor was an antioxidant compound which were in cherry fruit extract. Variation of the volume ratio between cherry fruit extract and 1 mM AgNO3 solution was 1: 3, 1: 4, 1: 5, 1: 6, and 1: 7 and the variation of contact time were 5, 15, 30, 45, 1, 2, 3 hours, and 1, 2, 7 days. The most optimum results of silver nanoparticles were synthesized with 1 : 4 volume ratio and 1 hour contact time. From the results of selectivity test, it was known that silver nanoparticles were made selective toward Hg and Fe metal. The sensitivity test toward Hg metal, it was known that NPP can detect mercury metal with the smallest concentration of 16,7  ppb.
Facile Detection of Oil Adulteration using UV-Visible Spectroscopy Coupled with Chemometrics Analysis Nina Gusti; Dinda Oktarina; Rina Elvia; Euis Nursa’adah; Rendy W Wardhana; Agus Sudaryono; M. Lutfi Firdaus
Science and Technology Indonesia Vol. 6 No. 1 (2021): January
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1587.291 KB) | DOI: 10.26554/sti.2021.6.1.14-18

Abstract

Engine and machine oils, better known as lubricant, is a fast-moving part within the motorcycle and automobile industries. Due to its high demand, these oils are often counterfeited by irresponsible people to get more profit. The thing most often done to adulterate oil is by mixing it with other low-quality or used oil. Here, we propose a simple analytical method to identify oil adulteration by using UV-Visible spectroscopy. A number of 425 genuine and adulterated oils were used as samples. After appropriate dilution using n-hexane, the samples were analyzed by UV-Visible spectrophotometer followed by Principle Component Analysis (PCA) and Principle Component Regression (PCR) as part of the chemometrics analysis. The results show that prediction samples were accurately classified into their corresponding groups with PCA scores of 49% and 27% for principal component 1 and 2, respectively. PLS model achieved a good prediction to detect lubricant oil adulteration, with R-Square of predicted and reference samples were 0.9257 and 0.9204, respectively. The proposed method shows a promising alternative to the conventional chemical method using a more sophisticated instruments such as GC-MS and HPLC for oil or other organic compound identification.