Search

The advanced oxidation process (AOP) is a promising remediation technology for persistent organic pollutants in the environment. We herein investigated the ability of a magnetic carbon microsphere (CM)-based composite catalyst (Fe3O4-CM) to catalyze sodium persulfate (Na2S2O8, SPS) for the remediation of marine sediments contaminated with polycyclic aromatic hydrocarbons (PAHs), The effectiveness of the process parameters, catalyst dose, and initial pH were investigated. Using the optimized conditions, 87% of the PAHs were removed in the Fe3O4-CM-CM/PS system within 24 h, compared with 59% and 41% in the case of persulfate (PS) and CM/PS (PS concentration® 1.3 x 10-5 M, catalyst concentration = 5.0g/L, pH = 6.0) alone. The PAH reduction rate can be attributed to the uniform graphitic structure of Fe3O4-CM-ClVI, which serves as an effective matrix for PAH degradation by providing additional active sites. The degradation of the PAHs was related to the number of rings in their structure, as confirmed by the higher degradation efficiency observed for high aromatic ring PAHs (HPAHs). Thus, we herein demonstrated the CM-mediated electron transfer catalysis of the surface functional groups at circumneutral pH values in the Fe3O4-CM-CM/PS system to the highly efficient removal of PAHs from contaminated sediments. [ABSTRACT FROM AUTHOR]

In this study, a copper nanoparticle-modified titanium dioxide (CuO-TiO2) catalyst was synthesized using the coprecipitation method with Cu(NO3)2 as the active component for the electrochemical oxidation (ECO) of ammonia (NH3). The voltammetric behavior and characterization of the electrocatalyst, including oxidation behavior, were investigated using linear sweep voltammetry (LSV), polarization, and chronoamperometric measurements, combined with SEM, FTIR, XRD, EEFM and XPS. SEM and XRD spectroscopy revealed that CuO particles were highly dispersed on the anatase phase of the TiO2-supported surface. The XPS and FTIR analysis indicated that CuO was firmly deposited through the linkage of CuOTi bonding to the TiO2 base and the sample exhibiting the stretching vibration mode associated with the CuO bonds of the CuO nanoparticle. Results of EEFM analysis indicate that significant excitation/emission plots located at 218/280 nm is associated with the CuO nanoparticle. The LSV oxidation ability could explain the catalytic activities of the CuO-TiO2 electrocatalysts, and NH3 oxidation peak current on the CuO-TiO2 electrocatalyst increased as scan rates increased, indicating that the adsorption-controlled process occurred at the electrocatalyst. [ABSTRACT FROM AUTHOR]

In this report, we describe the preparation and electrochemical characterization of a Pt electrocatalyst, which was synthesized from hexachloroplatinic acid, using the incipient wetness impregnation method. This carbon mesoporous materials (Pt-CMMs) electrocatalyst was used for catalyzing the oxidation of methanol and its oxygen-reduction reaction. The electrocatalytic oxidation of methanol was studied using linear-sweep voltammograms (LSV), polarization and chronoamperometric measurements. Phase characterizations and morphological analyses were performed using 3D excitation-emission fluorescent matrix (EEFM) spectroscopy, UV-Vis absorption measurements, and X-ray diffraction (XRD) and environmental scanning electron microscopy (ESEM) techniques; the ESEM system was equipped with an energy-dispersive spectrometer (EDS). The oxidation capacity measured using a LSV might explain the high activity exhibited by the Pt-CMM electrocatalysts in methanol-tolerant oxygen reduction, and the results demonstrated that the potential and current density of the main reaction peak of the Pt-CMMs electrocatalyst changed during the reaction. Moreover, EEFM spectroscopy and XRD were determined to be appropriate and effective methods for characterizing Pt clusters that enhance their intrinsic emission from Pt-CMMs electrocatalysts in electrocatalytic-treatment systems. Furthermore, the ESEM-EDS results showed that fresh Pt nanoparticles were highly dispersed on CMMs and featured a 20 nm diameter and a narrow particle-size distribution. [ABSTRACT FROM AUTHOR]

The distribution, enrichment, accumulation and potential ecological risks of mercury (Hg) in the surface sediments of Kaohsiung Harbor. Taiwan, were investigated. Sediment samples from 20 locations throughout Kaohsiung Harbor were collected quarterly from 2006 to 2011, and characterised for mercury, aluminium, water content, organic matter, total nitrogen, total phosphorous, total grease and grain size. The results showed that Hg concentrations varied from 0.06-6.73 mg kg-1 with an average of 0.54 ± 0.71 mgkg-1. The spatial distribution of Hg reveals that the Hg concentration is relatively higher in the river mouth regions, especially at the Love River and Canon River mouths from where it gradually diminishes toward the harbour entrance region. The results from the enrichment factor and geo-accumulation index analyses reveal that the sediments near the Love River and Canon River mouths experience severe enrichment and strong accumulation of Hg that originates from upstream sources of pollution. The assessment of biological effects indicates that concentrations of 92.5% Hg found in the sediment are higher than effects range low, implying that the harbour sediments may cause an adverse impact on aquatic lives. The results of a potential ecological risk index indicate that the sediment has higher to serious levels of ecological potential risks. [ABSTRACT FROM AUTHOR]

Marine microorganisms still belong to untapped natural resources and can harness a rich source of lipase enzymes with the potential industrial applications. Thraustochytrids are heterotrophic fungus like protists that can dissolve organic matters via enzymes. It has been less explored so far. Lipase is one of the most widely used enzymes, crucial to many biotechnological and industrial processes, including the food, paper, and oleochemical industries, as well as in applications related to pharmaceuticals. However, its application is relatively expensive and challenging due to its instability and aqueous solubility. Immobilization is a commonly employed strategy to enhance lipase activity, and it has proven to be a successful approach. In comparison to free lipase, immobilized lipase on nanomaterials (NMs) has demonstrated superior properties, including greater pH and temperature stability, a longer stable duration, and the ability to be recycled. However, under specific circumstances, protein loading is comparatively decreased and lipase immobilization on NMs might also occasionally result in activity loss. The overall performance of immobilized lipase is influenced by the NMs types and properties. This review addresses thraustochytrids potential for lipase production, emerging extraction techniques employing nanomaterials, and the significance of various techniques for lipase immobilization. The immobilized lipases' potential for several applications has also been taken into account. [ABSTRACT FROM AUTHOR]

Marine polysaccharide degrading enzymes are pivotal for catalyzing glycosidic linkages' breakdown in polysaccharides, yielding low-degree oligosaccharides and monosaccharides. These enzymes show substantial potential in diverse biotechnological applications. Marine polysaccharides and their derivatives exhibit anti-inflammatory, antiviral, anticoagulant, and anticancer properties, and are used in food additives with potential health benefits such as prebiotic oligosaccharides. Research explores pharmaceutical applications of marine polysaccharide degrading enzymes, including novel drug delivery and therapeutic bioactive oligosaccharide production. These enzymes are crucial for depolymerizing marine polysaccharides, providing energy and nutrients to microorganisms, and contributing to nutrient cycling and ecological balance. The breakdown of marine polysaccharides is vital for the global carbon cycle and helps regulate atmospheric carbon dioxide levels, impacting environmental sustainability. This comprehensive review delves into marine polysaccharide degrading enzymes, emphasizing carrageenase, agarase, chitinase, chitosanase and alginate lyase. Challenges such as low yields, poor stability, and high costs prompt solutions through metabolic engineering, enzyme immobilization, and engineering, enhancing resistance and efficiency. These advancements amplify the value of marine polysaccharidedegrading enzymes in biotechnological and environmental contexts. [ABSTRACT FROM AUTHOR]

Sargassum spp., a predominant seaweed speciesin Taiwan's coastal waters, exhibits a broad spectrum of bioactivities. In the present study, we investigated four Sargassum species viz., S. crassifolium, S. siliquosum, S. hemiphyllum, and S. hemiphyllum var. chinense for various bioactivities. From the four species, we made eight fucoidan extracts, namely SC, SCH, SS, SSH, SH, SHH, SHC, and SHCH with or without a compressional puffing pretreatment. The compressionalpuffing process increased the extraction yield of fucoidan and decreased levels of impurities (proteins and polyphenols). Among the eight fucoidans, SS (IC50 DPPH 0.46±0.01 mg/mL; IC50 ABTS•+ 0.09±0.00 mg/mL; FRAP value 67.4±0.9 μmol/g extract, vitamin C equivalent) and SHC (IC50 DPPH 0.53±0.17 mg/mL; IC50 ABTS•+ 0.11±0.00 mg/mL; FRAP value 55.1±0.6 μmol/g extract, vitamin C equivalent) displayed the highest antioxidant activity; SS (36.4±10.1% at 5 mg/mL for α-amylase; 96.3±0.2% at 1 mg/mL for α-glucosidase) and SHC (35.0±2.2% at 5 mg/mL for α-amylase; 96.5±0.2% at 1 mg/mL for α-glucosidase) showed the strongest α-amylase and α-glucosidase inhibitory activities; SH, SHH and SHC had the most potent anti-inflammatory activity; and SHH had a greatest protective effect against damage to pancreatic cells. Hence, SS, SH, SHH, and SHC may be effective health-promoting agents for nutraceutical products. [ABSTRACT FROM AUTHOR]

The pineapple leaves (PL) left over in the fields after pineapple harvest or burnt out, generate waste which contributes to the release of greenhouse gases. As pineapple is one of the most harvested crops in the world, the quantity of pineapple trash and its disposal methods are challenging. The composition of PL waste makes it unique to encounter the increasing demand for renewable energy and other useful products. This review is focused on the production of different biorefinery products and miscellaneous products from PL waste. The high cellulose content in PL makes it a potential feedstock for the production of different biorefinery products like bioethanol, oligosaccharides, nitrocellulose, and humic acid apart from this, waste is also useful for the production of different products like pineapple leaf fibres, fake eyelashes, organic leather, pulp and paper. Although the opportunities, future perspectives, and challenges concerning PL waste utilization to value-added goods were also addressed. It has been demonstrated that pineapple waste conversions lower waste creation, and the products produced by the conversion would promote the 'waste-to-wealth' notion. [ABSTRACT FROM AUTHOR]

Mud lobsters are burrowing crustaceans that are widely distributed in the Indo-Pacific region, including the Philippines. However, they are somehow neglected in scientific studies in the country. The increasing risks brought by this pandemic further impede field surveys as mobilization is highly regulated. Hence, the use of social media platforms was explored to study the ecology and exploitation of mud lobsters in the Philippines. This study used content analysis of YouTube videos. Key terms were searched to identify contents such as 'Philippines,' 'mud lobsters,' and local terms like 'bulaso,' 'uson,' and 'urong.' A total of 30 videos were analyzed. Videos were posted from 2015–2021 from at least 10 provinces. Results reinforce the already known wide distribution of mud lobsters in mangrove forests, fishponds, and rice fields beside mangroves. Still, there were notable mud lobster behaviors observed such as 1) surfacing during the rainy season, 2) the timing of which disturbed burrow is repaired, and 3) conspecific repulsion – all of which were not previously documented. Empty burrows were also found inhabited by the terrestrial crab Cardisoma carnifex. Mud lobsters were commonly caught using bamboo traps, but some had developed unique fishing techniques such as mound disturbance and the tali-tali method. Alarmingly, this study also found the use of toxic chemicals for illegal fishing activity. This study provides evidence on the potential use of social media to study aquatic organisms. Additional knowledge on mud lobster ecology and baseline information on some aspects of its fishery in the Philippines was observed. Social media can be useful for surveillance and ecological studies but could not be used as an alternative method for in-depth biological and taxonomic studies, where actual specimens are necessary. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the feasibility of lightweight aggregate (LWA) made from dredged harbor sediment and basic oxygen furnace (BOF) slag to increase their reutilization. The effects of preheating, sintering and raw materials proportion on the properties of LWA were discussed in term of particle density, water absorption, and compressive strength. Microscopic structure, water-soluble chloride and heavy metals leachability of the LWA were also examined. Results showed that the mixture of the dredged harbor sediment and BOF slag under the manufacturing process with preheating temperature at 500 °C for 10 min and sintering temperature at 1175 °C for 15 min was conducive to be a low water absorption and high strength LWA, which had as low as 1.73 gcm-3 and 3.45% for dry particle density and water absorption respectively. Its compressive strength reached 23.2 MPa when the addition of BOF slag was up to 27%. The LWA prepared in this study also have very low water-soluble chloride and heavy metals leachability, all compliant with Taiwan regulatory standards, thus would be suitable for further civil engineering application. The results of this study provide useful information on co-treating of wastes and recycled resources as LWA. [ABSTRACT FROM AUTHOR]

Some industrial wastewater containing complicated contents (e.g., heavy metals and organics) and extensive concentration-variation cannot be well-treated by physical-chemical treatment processes. In order to obtain the feasible electrochemical technique, an electrocatalytic-membrane process (ECMP) was established to treat such wastewater from a mint factory in Taiwan. Wastewater samples with pollutants of Cu2+ Ni2+ and chemical oxygen demand (COD) were categorized into three types based on pH and concentrations. The complexity of wastewater is attributed that a verity of chemical reagents and manufacturing methods are employed to produce different kind of coins. In this study, each type of wastewater was treated by the ECMP and integrated with other techniques to find out the appropriate procedures. Results indicate that the sole ECMP can effectively remove the Cu2+, Ni2+, and COD when the wastewater is with relatively low pH (around 3-5 ), low COD (around 50 mg L-1), and high concentration of heavy metals (Cu2+ concentration over 500 mg L-1). However, the ECMP should combine with pH -adjustment to effectively remove the Cu2+ Ni2+, and COD when the wastewater is with very low pH (close to 1), high COD (over 200 m g L-1), and high concentration of heavy metals. In addition, the ECMP has to link the electrocoagulation (ECG) to decrease the Cu2+, Ni2+, and COD concentration when the wastewater is with neutral pH (around 7), middle-level COD (around 130 m gL-1), and low concentration of heavy metals (Cu2+ concentration around 1.0 mg L-1). Accordingly, the ECMP integrated with other treatment processes gains potential to treat refractory wastewater. [ABSTRACT FROM AUTHOR]

In this study, the degradation of methylene blue (MB) was conducted to evaluate the feasibility of using persulfate oxidation activated with iron oxide (FeO) magnetic particles. The results demonstrated that the decolorization rate of MB increased with increasing FeO concentration, exhibiting maximum efficiency at pH0 3.0. The kinetics of MB was studied in the binary FeO catalyst and persulfate oxidation system. The surface properties of FeO before and after reaction was analyzed using cyclic voltammogram (CV), three-dimensional excitation-emission fluorescence matrix (EEFM) spectroscopy, zeta potential, particle size distribution measurements, X-ray diffraction (XRD) and environmental scanning electron microscopy-energy dispersive X-ray spectrometry (ESEM-EDS). The CV data indicated that a reversible redox reaction holds the key to explaining the significant activity of the catalyst. EEFM was used to evaluate the catalyst yield of FeO by fluorescence intensity plots with excitation/ emission at 220/300 nm and 260/300 nm. The XRD and ESEM-EDS results confirmed the presence of FeO in the catalyst. [ABSTRACT FROM AUTHOR]