Spherical and Rod-shaped Gold Nanoparticles for Surface Enhanced Raman Spectroscopy

Raman Spectroscopy offers an in-situ, rapid, and non-destructive characterization tool for chemical analysis of diverse samples with no or minimal preparation. However, due to the inherent weak signal of conventional Raman spectroscopy, surface plasmon resonance features of noble metal nanoparticles have been utilized to conduct Surface Enhanced Raman Spectroscopy (SERS) in detecting trace label contaminants in foods and foodstuffs. In this effort, we synthesized gold nanoparticles (AuNPs) by reduction of chloroauric acid (HAuCl4) with sodium citrate dehydrate. We prepared different sizes of AuNPs at a fixed temperature (100 oC) but with varying pHs of 4 and 8. The as-synthesized AuNPs were characterized by UV-Vis spectroscopy, dynamic light scattering (DLS), and Field Emission Scanning Electron Microscopy (FE-SEM). FE-SEM micrographs revealed spherical AuNPs with an average diameter of approx. 55 nm and rod-shaped AuNPs with an average length of approx. 170 nm for sample synthesis at pH 8 and 4, respectively. The effectiveness of the as-prepared AuNPs for SERS is tested by detecting Rhodamine 6G diluted at a trace level. This study suggests that plasmonic nanoparticles coupled with SERS have great potential for broad applications in detecting other trace amounts of hazardous chemicals in foods and foodstuffs.Comment: 4 pages, 5 figure

Solid-state Synthesis of Phase Pure CuBi2O4 by Sequential Ball Milling

Bismuth-based metal oxides are an intriguing class of photoelectrode materials that can potentially enable large-scale solar hydrogen production via photoelectrochemical (PEC) water-splitting. For realizing such PEC devices, Kusachiite (copper bismuth oxide) is one of the most promising photocathode materials for high solar to hydrogen efficiency. Here we attempt to synthesize phase pure copper bismuth oxide (CuBi2O4) nanopowders using a facile solid-state reaction technique subsequently sintered at 750 0C for 4 h in air. These CuBi2O4 (CBO) powders have been further sequentially ball milled (SBM) up to 25 h to elucidate the milling duration effect on the optical bandgap of the ball milled CuBi2O4 (SBM-CBO). The structural, optical, and Raman studies suggest that phase pure tetragonal CBO could be grown from raw CuO and Bi2O3 powders. The variations in morphology and chemical composition of CBO with increasing milling hours were examined using field emission scanning electron microscopy (FE-SEM) and Energy Dispersive X-ray (EDX) microanalysis, respectively. The optical bandgap was measured in the range of 1.70 - 1.85 eV from the UV-VIS-NIR Diffuse reflection data of SBM-CBO powders. The CBO photocathode materials with variable structural and optical properties could be a promising candidate for self-sustained PEC generation of hydrogen fuel.Comment: 4 pages, 5 figures, 2022 4th International Conference on Sustainable Technologies for Industry 4.0 (STI

Green hydrogen based power generation prospect for sustainable development of Bangladesh using PEMFC and hydrogen gas turbine

Bangladesh focuses on green energy sources to be a lesser dependent on imported fossil fuels and to reduce the GHG emission to decarbonize the energy sector. The integration of renewable energy technologies for green hydrogen production is promising for Bangladesh. Hybrid renewable plants at the coastline along the Bay of Bengal, Kuakata, Sandwip, St. Martin, Cox’sbazer, and Chattogram for green hydrogen production is very promising to solve the power demand scarcity of Bangladesh. Hydrogen gas turbine and hydrogen fuel cell configured power plant performances are studied to observe the feasibility/prospect to the green energy transition. The Plant’s performances investigated based on specification of the plant’s units and verified by MATLAB SIMULINK software. Fuels blending (different percent of hydrogen with fossil fuel/NG) technique makes the hydrogen more feasible as turbine fuel. The net efficiency of the fuel cell-based combined cycle configuration (74%) is higher than that of the hydrogen gas turbine-based configuration (51.9%). Moreover, analyses show that the increment of combined cycle gas turbine efficiency (+18.5%) is more than the combined cycle PEMFC configuration (+14%). Long-term storage of renewable energy in the salt cavern as green hydrogen can be a source of energy for emergency. A significant share of power can be generated by a numbers of green power plants at specified places in Bangladesh

Assessing challenges for implementing Industry 4.0: implications for process safety and environmental protection

Researchers and practitioners are giving significant attention to Industry 4.0 due to its numerous benefits to manufacturing organizations. Several aspects of Industry 4.0 have been studied in the literature. However, studies on the challenges for implementing Industry 4.0 in manufacturing operations have received less attention. To address this gap, this study identifies a set of challenges (framework) for implementing Industry 4.0 in manufacturing industries. This framework is evaluated in the leather industry of Bangladesh aided by a novel multi-criteria decision-making method named Best-Worst method (BWM). The findings of the study showed that ‘lack of technological infrastructure’ is the most pressing challenge that may hurdle the implementation of Industry 4.0 whereas ‘environmental side-effects’ is the less among the challenges that may hinder implementation of Industry 4.0 in the Bangladeshi leather industry. This result may help decision makers, industrial managers and practitioners in the Bangladeshi leather industry to realize the actual challenges confronting them when attempting to implement Industry 4.0 and focus their attention on how to address these challenges to pave ways for a successful implementation of Industry 4.0

Impacts of Landfill Leachate on the Surrounding Environment: A Case Study on Amin Bazar Landfill, Dhaka (Bangladesh)

Currently, a total of about 15,000 tons/day of waste is generated in the entire Dhaka city with an average per capita waste generation of 0.641 kg/day. Only 37% of this waste is collected and dumped into the two sanitary landfill sites, which is the only waste management system in Dhaka. To investigate the impact of landfill leachate of Amin Bazar landfill on the environmental compartments, a total of 14 composite samples (two leachates, three surface water, three groundwater, three soil, and three plants) were collected and analyzed for physicochemical parameters and heavy metal(loid)s concentration. Based on the result of physicochemical parameters, all results were found higher in the leachate samples than the permissible limit. The heavy metal(loid)s in leachate samples have a value of high levels of contamination. Surface water, groundwater, soil, and vegetation are all polluted as a result of high levels of metal contamination. Although the Water Quality Index values of the samples based on heavy metal(loid)s concentrations were within the acceptable range, heavy metal concentrations in the soil and plants were quite high. The concentrations of lead (Pb—8 mg/kg), cadmium (Cd—0.4 mg/kg), chromium (Cr—2.26 mg/kg), and cobalt (Co—1.72 mg/kg) in all plant samples were found to be higher than the allowable limit. The individual concentration of arsenic (As—0.021 mg/L) in the leachate was higher than the maximum allowed limit. Inverse Distance Weighted analysis through ArcGIS showed that landfill leachate has the maximum probability of contaminating the surrounding environment with heavy metal(loid)s. Results showed that samples collected near the landfill have higher concentrations of heavy metal(loid)s than others, which establishes the contribution of landfill leachate in contaminating the environment with heavy metal(loid)s. The improper leachate management of landfill has a high impact on the environment

Biomass-based curing agents for sustainable leather processing

The biomass utilization without purification and fractionation through a non-selective manner is the best option for high conversion efficiency. Leftover and abundant plant biomass can be a source of preservatives if they keep antimicrobial activity against spoilage microorganisms. Traditionally, 50% w/w sodium chloride (NaCl) is employed for hides and skin preservation (curing). However, enormous water pollution, aquatic toxicity, soil infertility, and high chemical consumption make it questionable. This study investigates biomass-based curing (BBC) agents from Cynodon dactylon grass and Alzibia lebbeck leaves. The plant’s dry powder was directly applied over goatskin and evaluated curing efficiencies. The BBC formulations were user-friendly, highly biomass conversion efficiency (41-53% of raw wt.) and antimicrobial activity (against E. coli: 17-18 mm and B. subtilis: 15-17 mm), and preserved goatskin for 30 days like NaCl. It reduced the salinity and total dissolved solids (TDS) load from tannery-soaking effluent by 67-74% and 41-65%, respectively. The environmental efficiency index (EEI) revealed that BBC systems (EEI: 29.9-31.3) are around 1.5 times more environmentally sustainable than conventional curing (EEI: 20.7). Besides, the alternatives have no effect on the features of final leather. In conclusion, the ecofriendly BBC agents have the potential to minimize the heavy pollution of salt curing

Impacts of Landfill Leachate on the Surrounding Environment: A Case Study on Amin Bazar Landfill, Dhaka (Bangladesh)

Currently, a total of about 15,000 tons/day of waste is generated in the entire Dhaka city with an average per capita waste generation of 0.641 kg/day. Only 37% of this waste is collected and dumped into the two sanitary landfill sites, which is the only waste management system in Dhaka. To investigate the impact of landfill leachate of Amin Bazar landfill on the environmental compartments, a total of 14 composite samples (two leachates, three surface water, three groundwater, three soil, and three plants) were collected and analyzed for physicochemical parameters and heavy metal(loid)s concentration. Based on the result of physicochemical parameters, all results were found higher in the leachate samples than the permissible limit. The heavy metal(loid)s in leachate samples have a value of high levels of contamination. Surface water, groundwater, soil, and vegetation are all polluted as a result of high levels of metal contamination. Although the Water Quality Index values of the samples based on heavy metal(loid)s concentrations were within the acceptable range, heavy metal concentrations in the soil and plants were quite high. The concentrations of lead (Pb—8 mg/kg), cadmium (Cd—0.4 mg/kg), chromium (Cr—2.26 mg/kg), and cobalt (Co—1.72 mg/kg) in all plant samples were found to be higher than the allowable limit. The individual concentration of arsenic (As—0.021 mg/L) in the leachate was higher than the maximum allowed limit. Inverse Distance Weighted analysis through ArcGIS showed that landfill leachate has the maximum probability of contaminating the surrounding environment with heavy metal(loid)s. Results showed that samples collected near the landfill have higher concentrations of heavy metal(loid)s than others, which establishes the contribution of landfill leachate in contaminating the environment with heavy metal(loid)s. The improper leachate management of landfill has a high impact on the environment

A smart device of data acquisition with emergency safety features for laboratory furnaces

Laboratory furnaces or ovens are found in scientific, forensic, medicinal, and material processing labs. They provide precise temperature control and homogenous heating for samples in industrial and research applications but cannot measure the sample's interior temperature and most of them do not have the facility to store temperature data. Moreover, a furnace cannot promptly shut off if a sample or the furnace catches fire due to overheating or an electrical failure. To solve these problems, in this work, an intelligent, automated add-on device with wireless monitoring and emergency safety features to use with any commercial furnace or oven is presented. The device can individually measure furnace and sample temperatures at the same time using a two-channel K-type thermocouple unit. The system can store the real-time temperature data generated by the thermocouples, display it on LCD (Liquid Crystal Display) and give the facility to observe this real-time data from anywhere within an area of 800–1000-m radius using the portable wireless monitor device without the need for Wi-Fi or internet. Additionally, the device can quickly detect fire or overheating, immediately cuts the power automatically, activates a loud alarm and dials the user's phone itself using Global System for Mobile Communication (GSM) technology to warn them

Development of Flexible Composite Sheet with Chrome Shavings Using Polyvinyl Alcohol as a Cross-Linker

Leather processing generates a huge amount of chromium (Cr) containing wastes, and one of them is chrome shavings (CS), which frequently end up in landfills. It may be harmful to the environment and human health due to the oxidation of Cr(III) to poisonous Cr(VI). Herein, CS and polyvinyl alcohol (PVA) are used for the preparation of flexible CS-PVA composite sheets, using CS as a skeletal and PVA as a cross-linker by a simple and facile technique. CS-PVA composite sheets are characterized by FT-IR, SEM, STA, and UTM. FT-IR analysis of CS-PVA composite sheets indicated the existence of dominating peaks corresponding to collagen amide bands as well as PVA characteristic bands, and it demonstrates the uniformity of the developed composite sheets. When the amount of PVA is increased, the tensile strength of CS-PVA composite sheets increases from 0.21 to 4.17 N/mm2. With increasing of the amount of PVA, the softness decreases from 6.47 to 3.7 mm, and SEM shows decreasing of pores in the composite sheet. The addition of more PVA makes CS-PVA composite sheets more thermally stable. This facile method of preparing CS-PVA composite sheet is low-cost and eco-friendly, having potential applications in various fields, including clothing, leather goods, decoration, packaging, and footwear products, as well as presenting promising platforms for effective utilization of industrial waste materials

Development and validation of a modified QuEChERS method coupled with LC-MS/MS for simultaneous determination of difenoconazole, dimethoate, pymetrozine, and chlorantraniliprole in brinjal collected from fields and markets places to assess human health risk

An effective and sensitive analytical method was developed to quantify the most common pesticide residues (difenoconazole, dimethoate, pymetrozine, and chlorantraniliprole) used for brinjal cultivation in Bangladesh. The quantification of the analytes was done using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The samples were extracted using a modified QuEChERS method and followed by purification with dispersive solid phase extraction (d-SPE) sorbents (PSA, GCB, and C18). Matrix-matched calibration with a regression coefficient R2 ≥ 0.9964 were used to minimize the brinjal matrix effect. The method was validated in quintuple (n = 5) at five different spiked levels (8–400 μg/kg) having recoveries in the range of 70.3–113.2% with relative standard deviations RSDs ≤6.8%, limits of detection (LOD) and limits of quantification (LOQ) was in the range of 0.15–0.66 μg/kg and 0.4–2.0 μg/kg, respectively, for the four analytes. A total 100 samples (50 samples directly from fields of Jessore district, Bangladesh and 50 samples from local market of Dhaka, Bangladesh) were collected to analyse the pesticides residue. The result showed that pesticides residue was found in both the field and market collected samples, 54% and 38%, respectively. The overall mean residue levels of four pesticides in field samples were significantly higher than those of market samples. Moreover, 20% of the field samples and 10% of the market samples had dimethoate residues, which were the most abundant among the four analytes and it ranged from 0.017 to 0.252 mg/kg. In terms of health risk assessments, dimethoate showed the highest estimated daily intake (EDI) and hazard quotient (HQ) values that are 3.02 × 10−5 mg/kg/day and 1.51%, respectively, in field samples. Till now, there have been no regulations or guidelines for the maximum admissible pesticide residue in Bangladesh. Therefore, the above findings will be an initial step for the regulatory authorities of Bangladesh to implement regulations and guidelines for pesticide usage