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The current research involved the synthesis of hydroxyapatite powders using Faunus ater shell (FaS), which is a snail found in brackish water, as a source of calcium. Hydroxyapatite (HAp) is produced through the hydrothermal synthesis of FaS, employing calcination temperatures at 900 °C (HAp900) and 1000 °C (HAp1000). The samples underwent analysis through scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) to determine the phases present. Additionally, quantitative chemical analysis of the synthesized and heat-treated powders was conducted using X-ray fluorescence (XRF) spectroscopy. XRD analysis determined that HAp900 and HAp1000 exhibited amorphous structures, with the additional presence of Tetracalcium Phosphate (TTCP) phase detected in HAp 900. Furthermore, XRF analysis was conducted on both samples, revealing molar ratios of Ca/P as 2.56 and 1.67 for HAp900 and HAp1000 respectively. The FTIR spectrum revealed that the synthesized HAp contains phosphate, carbonate, and hydroxyl groups.

Chemistry is one of the subjects taught in State Senior High Schools (SMAN), especially in Natural Sciences (IPA). The problem with chemistry subjects is that it is difficult to practice in the laboratory because laboratory facilities such as space, equipment and chemicals are expensive. As a result, chemical laboratory practices were only sometimes carried out. Several lecturers and students from the Department of Chemistry, FMIPA Unand Kimia Unand, carried out service activities at SMAN 16 Padang through laboratory practice using materials and equipment that were cheap and readily available in the surrounding environment. This community service aims to train teachers and students to carry out chemistry practicums using simple materials and equipment available around them. The training was given to chemistry subject teachers and students in the science laboratory at SMAN 16 on 17 and 21 November 2022. The material was practised in oxidation and reduction (redox) and electrolysis reactions. The activity went smoothly; the students enthusiastically carried out the practicum. Through the results of this simple chemistry practicum, students can design and carry out chemical experiments using simple tools and materials, conduct direct observations of chemical processes, practice scientific thinking, attitude and work skills and analyze and solve various scientific processes using scientific methods. SMAN 16 hopes that this activity will continue with different topics.

The Community Service Team of the Chemistry Department has worked closely with the Taman Pendidikan Qur'an (TPQ) and Rumah Tahzhul Qur'an (RTQ) Raudhatul Adzkia Jorong Dalam Koto Nagari Koto Tangah in solving problems faced by partners. The pond catfish farming business supports smooth operational costs and has been running for over a year, but these results still need to be improved for TPQ and RTQ. This activity aims to develop a catfish farming business accompanied by an aquaponic cultivation business to increase income from TPQ and RTQ. The benefit of this activity is that the partners have an Aquaponics business which is cultivating catfish and vegetable plants in the fish pond. The Community Service Team transferred knowledge to partners, especially in cultivating aquaponic plants through entrepreneurship. The activities of the Community Service Team in helping partners are a form of the Andalas University Higher Education Tri Dharma. The method applied to support the realization of this community service program was through supervision, program socialization, and implementation of activities. The result of this activity was that partners could run an aquaponics business to increase income to meet the operational costs of education and teacher salaries.

Seberang Padang Village, South Padang District, is next to Padang City, which has approximately 200 families. This location is a crossing area between Padang-Painan, in West Sumatra. The community consists of two existing traditional markets that sell daily necessities. Besides that, there is also one elementary school, two junior high schools, and one high school. The global Covid-19 pandemic certainly affects the community's daily activities and learning activities, including children, elementary school students, middle and high school students, and the village community to fulfil their basic needs. Furthermore, the main problem of Covid-19 is not only about the effects caused by the virus on sufferers but also about its high-speed transmission. Therefore, to educate the community around the Seberang Padang village, several Chemistry Lecturers and students at the Faculty of Mathematics and Natural Sciences at Andalas University did a community engagement. They taught the community about making disinfectants and hand sanitizers without alcohol that can overcome the occurrence of Covid-19 transmission. In addition, face masks were provided for the community, and the alms of food for underprivileged residents to push down the negative impact of Covid-19.

The aim of this study is to utilize fly ash from various sources on chemical and physical properties of cement type I (OPC). Utilization of fly ash can improve the strengthness of the cement. It can reduce the waste of fly ash by utilization into cement process. The procedure has been carried out on cement type I (OPC) with the addition of fly ash additives from various sources with concentration variations such as 10% and 20%. Utilization of fly ash as additives substance in cement works to improve the quality of cement. The main parameter in determining the quality of cement is determined by the compressive strength. The results of the compressive strength test showed that the addition of fly ash with a concentration of 10% had a higher effect on the compressive strength than the addition of a concentration of 20%. 5 types fly ash from various sources, fly ash from PT Sinar Mas gives greater compressive strength at 28 days. the addition of fly ash additives to OPC cement mixture has chemical and physical properties which are not much different from properties of PCC cement.

Seiring dengan perkembangan teknologi yang semakin pesat, buah-buahan banyak dikemas dalam kaleng. Buah kemasan kaleng merupakan makanan yang sering dikonsumsi oleh manusia pada saat ini. Penyimpanan buah kemasan kaleng dalam waktu yang lama dapat menyebabkan terjadinya migrasi logam berat terhadap buah yang ada di dalam kemasan. Pada penelitian ini sampel yang digunakan yaitu 3 jenis buah-buahan dalam kemasan kaleng masing-masing dengan lama penyimpanan yang berbeda. Preparasi sampel dilakukan menggunakan metode destruksi basah dengan menambahkan campuran HNO3 pekat 65% dan H2O2 15% (3:1). Kandungan logam Fe, Zn, Pb, dan Cd dalam sampel ditentukan menggunakan metode Spektrofotometri Serapan Atom (SSA). Nilai Indeks Risiko Kesehatan (IRK) didapatkan dari hasil perhitungan Asupan Logam Harian (ALH) per dosis yang disarankan oleh WHO. Nilai ALH diperoleh dari perhitungan konsentrasi logam dengan SSA, faktor konversi, dan rata-rata asupan logam per berat badan manusia. Kadar logam berat di dalam ketiga jenis sampel secara umum diperoleh Fe>Zn>Pb>Cd. Konsentrasi logam berat berbanding lurus dengan lama produk disimpan dalam kemasan kaleng. Semakin lama produk disimpan maka konsentrasi logam yang diperoleh semakin tinggi. Nilai IRK yang diperoleh dari pengujian sampel untuk logam Cd yaitu >1 dapat diasumsikan adanya potensi risiko kesehatan, sedangkan untuk logam Pb, Fe, dan Zn 1 dapat dinyatakan bahwa sampel yang diuji memiliki potensi risiko kesehatan terhadap manusia. Penelitian lebih lanjut diperlukan untuk memperjelas hubungan antara kontaminasi buah oleh logam berat dari kemasan kaleng.

Phenol (C6H5OH) is a common contaminant in wastewater. In certain concentrations, phenol can inhibit the activity of microorganisms and give adverse effects tohumanhealth, such as liver and kidney damage, perfect heart rate, and lower blood pressure. In this study, phenol was degraded with andwithoutN-doped TiO2under photolysis UV-light (10 Watts, λ = 365 nm) and visible-light (13 watt Philips, lux= 1400, λ = 465-640 nm)irradiation. The reductionof phenol concentrationwas measured by a UV-Vis spectrophotometer at a wavelength 200-400 nm. Some parameters such as catalyst dose, irradiation timesand type of light sources were studied. The XRD and DRS UV-Vis characterization confirmthat the nitrogen modified of titania catalyst potentially actives in visible-light. The N-doped TiO2is able to catalyze and improve the efficiency of phenol degradation in photocatalysissystem. Phenol with initialconcentration 8 mg/L was degraded by 33.89% and 30.51% without catalyst and increased to be 90.8% and 67.80%by additionof 15 mg N-doped TiO2catalyst under UV-light and visible-lightfor 210 minutes photolysis, respectively. From the results,irradiation using UV-light achieveshigherefficiency than visible-lightonphenol degradation.

The case of how handling the fresh fish which used the dangerous chemical material (formaldehyde) is still found in society, so that is why it is necesarry to find the safety way to handle the fresh fish in. It has been held the research about the influence of on the effect of some treatment in reduction the formaldehyde level on fish determined by spectrophotometry UV-Visible at wavelength 412 nm and 40°C. In the preliminary research the fish is soaked in formaldehyde liquid (100 mg/mL) for 24 hours, then washed, soaked and boiled. Then, the filtrate is reacted with Nash reagent. The yellow color which has formed was measured at λ 412 nm. The result shows there is the reduction of formaldehyde level in the sample about 43.9 % after washing, 33.3 % after soaking, 53.8 % after boiling. After that, the fish that was spread in the market which suspected containing the formaldehyde then washed, soaked and boiled. The result shows there is the reduction of formalin level in sample 1 about 22,7 % after washing, 17.0% after soaking, and 96.1 % after boiling. While in sample 2, 41.8 % after washing, 56.2 % after soaking, and 95.4 % after boiling.

ABSTRAK Penelitian tentang penentuan kandungan logam berat Fe, Cu, Pb, dan Cd dalam sedimen di sekitar keramba jaring apung di perairan danau Maninjau telah dilakukan. Sampel sedimen diambil pada 7 titik di lokasi dimana terdapat keramba jaring apung. Selanjutnya sampel didestruksi dengan HNO3 dan H2O2, kemudian kandungan logam diukur dengan menggunakan Spektrofotometer Serapan Atom (SSA). Dari hasil analisis sampel sedimen danau Maninjau diperoleh kandungan logam Fe berkisar antara 772,77 – 946,78 mg/kg, logam Cu berkisar antara 447,92 – 531,44 mg/kg, logam Pb berkisar antara 356,81 – 483,47 mg/kg dan logam Cd berkisar antara 249,68 – 318,95 mg/kg. Hasil yang didapat menunjukkan bahwa keempat logam telah melampaui ambang batas yang telah ditetapkan oleh Roseau National d Observation. Keywords: Logam berat, sedimen,dekstruksi

ABSTRACT The textile industry produce colored waste liquid that can contaminate the line water and its populations. A number of dyes are using in textile industry processes such as rhodamine-B and alizarine-S. Both of dyes are toxic for human life. In order to reduce the concentration that dyes is used the sonolysis method which have good efficiency and effective to degrade this pollutants. Sonolysis was performed using an ultrasound energy at 47 kHz. Catalyst ZnO is used to get better degradation. Rhodamine-B 2mg/L with 0.3 g ZnO addition, pH 5, temperature 40°C get 35.44% degradation after 60 minutes. If we used 3 mL H2O2 30% in the same condition the degradation up to 42.67% and with the combination of 0.3 g ZnO - 3 mL H2O2 as catalysts it got 91.99% after 90 minutes. Alizarine-S 20 mg/L with 0.5 g ZnO addition, pH 5, temperature 50°C was degraded up to 86.45% after 35 minutes. Furthermore, the degradation reached 95.79% if it used 0.5 g ZnO and 25 mL H2O2 30% at pH 5 and temperature 50°C after 35 minutes sonolysis. Keywords : rhodamine-B, alizarine-s, ZnO, H2O2