Nanocomposite design of graphene modified TiO2 for electrochemical sensing in phenol detection

Muhammad Nurdin,Maulidiyah Maulidiyah,Abdul Haris Watoni,Armawansa Armawansa,La Ode Agus Salim,Zul Arham,Dwiprayogo Wibowo,Irwan Irwan,Akrajas Ali Umar 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.1

This study is the stage of developing a phenol detection electrochemical sensor. Phenol is one of the organic pollutants harmful to human life and ecosystems. The development of this sensor was carried out by studying the use of TiO2 anatase as a modifier of graphene electrodes. The mass of TiO2 anatase was varied, while the mass of graphene and paraffin was fixed. The results showed that the TiO2 mass of 1.0 g was the best mass as a graphene electrode modifier. The use of this mass increases the oxidation current (Ipa) of phenol by 450 A, which is observed at an oxidation potential (Epa) of −0.30 V. The presence of interfering ions such as K+, Fe2+, and OH− can decrease the measurement current. However, based on the %RSD value, it shows that the performance of TiO2-graphene is in a good category, where the %RSD value obtained is 0.6%. TiO2-graphene electrodes can be used repeatedly for 12 days. Overall, this work demonstrates the potential of TiO2-graphene electrodes as electrode candidates for electrochemical-based phenol sensors.

Photoelectrocatalysis performance of Se doped-TiO2/Ti nanotube arrays for visible-light-driven degradation of diazinon pesticide

Nurdin Muhammad,Watoni Abdul Haris,Natsir Muhammad,Rahmatilah Sarifa,Maulidiyah Maulidiyah,Wibowo Dwiprayogo,Salim La Ode Agus,Sadikin Siti Naqiyah,Bijang Catherina Manukpadang,Umar Akrajas Ali 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.9

The modification of ternary metal oxide to improve the photoelectrocatalysis (PEC) properties of TiO2 photocatalyst is a hot issue in environmental and resource applications. Herein, we present a novel photoelectrocatalytst of Se doped-TiO2/Ti nanotube arrays (Se@TiO2/Ti-NTAs) for high-efficiency degradation of diazinon pesticide. The Se@TiO2/Ti-NTAs were prepared to treat the TiO2-NTAs in Se-TiO2 sol-gel for 10 min, which was followed by calcination in air at 200 °C for 1 h. Optical absorption spectroscopy of the Se@TiO2/Ti-NTAs indicated that there is a red-shift in the optical energy gap to 2.95 eV if compared to the pristine TiO2/Ti NTAs, which suggests that the new photoelectrocatalyst is photoactive under visible light irradiation. We evaluated the photoactivity of the sample by using it as the photoelectrocatalyst in the degradation of diazinon pesticides under the PEC process. The results showed that the Se@TiO2/Ti-NTAs can degrade 95.62% for 1 h under visible light irradiation, which is equivalent to the degradation rate constant of 0.0183 s−1. For comparison, the pristine TiO2/Ti NTAs only degrades the diazinon as high as 87.65%, even then under UV light irradiation. Our result also indicated that the Se@TiO2/Ti-NTAs promote active photoelectron transfer and active radical formation, such as •OH and •O − 2 , for rapid diazinon pesticide degradation. The Se@TiO2/Ti-NTAs photoelectrode should be a potential platform for environmental pollution treatment.

Diverse and predominantly sub-adult Epinephelus sp. groupers from small-scale fisheries in South Sulawesi, Indonesia

Nadiarti Nurdin Kadir,Aidah A. Ala Husain,Dody Priosambodo,Muhammad Jamal,Irmawati,Indrabayu,Abigail Mary Moore 한국수산과학회 2023 Fisheries and Aquatic Sciences Vol.26 No.6

Groupers (Family Epinephelidae) are commonly caught in data-poor small-scale multi-species fisheries for sale on both export and domestic markets. This study presents data on the species composition and size/life-stage structure of Epinephelus spp. groupers caught by small-scale fishers and sold locally in the Indonesian province of South Sulawesi. Data were collected from fishing ports and local markets at 12 sites representing the three seaways around South Sulawesi (Makassar Strait, Flores Sea, Gulf of Bone). Each specimen (n = 3,398) was photographed alongside an object of known length, and total length (TL) was obtained using the Rapid Scaling on Object (RASIO). Of the 23 species identified, four (Epinephelus areolatus, Epinephelus ongus, Epinephelus quoyanus, and Epinephelus fasciatus) collectively comprised 69% of the catch, while the 13 least abundant species contributed less than 5%. The catch was dominated (67%) by the subadult life-stage, with just under 20% in the adult class. Juveniles dominated the catch of Epinephelus fuscoguttatus, a valuable export commodity. Observations of early maturity as well as the sizeable gap between length at first capture (Lc) and length at first maturity (Lm) indicate recruitment overfishing of most species, with the notable exception of Epinephelus rivulatus. The proportion of adult fish was low (≈5%–30%) for the twelve most abundant species (E. areolatus, E. ongus, Epinephelus quoyanus, E. fasciatus, Epinephelus coioides, Epinephelus faveatus, Epinephelus sexfasciatus, Epinephelus maculatus, Epinephelus bleekeri, Epinephelus corallicola, E. fuscoguttatus, Epinephelus polyphekadion). For two moderately abundant species (E. faveatus and E. malabaricus), TL < Lm for all specimens. The limited data available indicate spawning ratio is lower than reported from deep-water fisheries of E. areolatus and E. coioides. The results call for targeted research to fill knowledge gaps regarding the biology and ecology of groupers exploited mainly for domestic markets; highlight the need for species-level data to inform management policies such as minimum legal size regulations; and can contribute towards species-level status assessments.

Introduction of Geospatial Perspective to the Ecology of Fish-Habitat Relationships in Indonesian Coral Reefs: A Remote Sensing Approach

Shuhei Sawayama,Nurjannah Nurdin,Muhammad Akbar AS,Shingo X Sakamoto,Teruhisa Komatsu 한국해양과학기술원 2015 Ocean science journal Vol.50 No.2

Coral reef ecosystems worldwide are now being harmed by various stresses accompanying the degradation of fish habitats and thus knowledge of fish-habitat relationships is urgently required. Because conventional research methods were not practical for this purpose due to the lack of a geospatial perspective, we attempted to develop a research method integrating visual fish observation with a seabed habitat map and to expand knowledge to a two-dimensional scale. WorldView-2 satellite imagery of Spermonde Archipelago, Indonesia obtained in September 2012 was analyzed and classified into four typical substrates: live coral, dead coral, seagrass and sand. Overall classification accuracy of this map was 81.3% and considered precise enough for subsequent analyses. Three sub-areas (CC: continuous coral reef, BC: boundary of coral reef and FC: few live coral zone) around reef slopes were extracted from the map. Visual transect surveys for several fish species were conducted within each sub-area in June 2013. As a result, Mean density (Ind. / 300 m2) of Chaetodon octofasciatus, known as an obligate feeder of corals, was significantly higher at BC than at the others (p < 0.05), implying that this species’ density is strongly influenced by spatial configuration of its habitat, like the “edge effect.” This indicates that future conservation procedures for coral reef fishes should consider not only coral cover but also its spatial configuration. The present study also indicates that the introduction of a geospatial perspective derived from remote sensing has great potential to progress conventional ecological studies on coral reef fishes.

Harvested locations influence the total phenolic content, antioxidant levels, cytotoxic, and anti-inflammatory activities of stingless bee honey

Nurul Sharina Rasyidah Badrulhisham,Siti Nur Parvin Ab Hamid,Muhammad Aiman Haiqal Ismail,Yoke Keong Yong,Noraina Muhamad Zakuan,Hanis Hazeera Harith,Hasni Idayu Saidi,Armania Nurdin 한국응용곤충학회 2020 Journal of Asia-Pacific Entomology Vol.23 No.4

Kelulut honey (KH) is a natural product-derived food produced by stingless bees of Trigona or Meliponine species. Several studies have shown that the geographical origin of honey significantly affects its pharmacological properties. Thus, this study aims to characterise the pharmacological properties of KH harvested from different geographical locations. The total phenolic content (TPC), antioxidant levels, cytotoxic, and anti-inflammatory activities of pure KH harvested from three different locations (Sarawak, Pahang and Selangor) were compared. Among the samples, KH harvested from Selangor exhibited the highest TPC, antioxidant levels, and cytotoxic activity against MDA-MB-231 and MCF-7 cells, followed by KH harvested from Sarawak and Pahang. The IC 50 of MCF-7 cells treated with KH harvested from Selangor was at least 2-fold lower than the IC 50 of MDA-MB-231 cells, suggesting that KH is more cytotoxic to oestrogen receptor (ER)- and progesterone receptor (PR)-positive (MCF-7) compared to triple-negative (MDA-MB-231) breast cancer cells. Two non-cytotoxic concentrations (1% and 0.5%; v/v) were selected for the anti-inflammatory assay using lipopolysaccharide (LPS)-induced RAW 264.7 cells. KH harvested from Selangor and Pahang (at a concentration of 1%; v/v) significantly inhibited nitric oxide (NO) production in LPS-induced RAW 264.7 cells compared to control cells. These findings provide evidence that the geographical origin of KH may indeed influence its pharmacological properties. Our data suggest that KH harvested from Selangor has a better quality compared to KH harvested from Pahang and Sarawak based on its high TPC, antioxidant levels and anti-inflammatory activity. Furthermore, it exhibits in vitro anticancer potential in breast cancer cell lines.

Sol-gel TiO₂/Carbon Paste Electrode Nanocomposites for Electrochemical-assisted Sensing of Fipronil Pesticide

Maulidiyah, Maulidiyah,Azis, Thamrin,Lindayani, Lindayani,Wibowo, Dwiprayogo,Salim, La Ode Agus,Aladin, Andi,Nurdin, Muhammad The Korean Electrochemical Society 2019 Journal of electrochemical science and technology Vol.10 No.4

The unique study of TiO₂ sol-gel modified carbon paste electrode (CPE) nanocomposites have been developed for electrochemical sensor detecting fipronil pesticide compound. We develop the easy synthesized TiO₂ via a sol-gel method and modified in CPE which applied electrochemical system as cyclic voltammetry (CV) because the concentration is proportional with current peaks. We discover the TiO₂ optimal mass used of 0.1 g which is compared with 0.7 g carbon and 0.3 mL paraffin. It has high-current anodic (Ip_a) of 1.13×10³ μA and high-current cathodic (Ip_c) -0.96×10³ μA in scan rate of 0.5 V/s. The limit of detection (LOD) of fipronil has been determined of 34.0×10^-5 μM in percent recovery of 0.8%. Its high-stability for lifetime TiO₂-CPE nanocomposites was expressed for 13 days which mean that can be used for detecting fipronil pesticide.