Sustainable Chemistry One World最新文献

Heavy metal contamination, such as aluminum (Al), is a significant global environmental concern. In addressing this issue, the ecologically-friendly method of phytoremediation using microalgae has been gaining attention. Our study explored the Al uptake capabilities of two green microalgae species, Scenedesmus sp. and Nannochloropsis sp., under laboratory conditions. Both species were exposed to varying Al concentrations (0.5, 1, and 2 mg L⁻¹) to evaluate their growth and tolerance levels over two weeks. Results showed that Scenedesmus sp. not only demonstrated tolerance to Al up to 2 mg L⁻¹ but also had an enhanced growth rate at the 2 mg L⁻¹ concentration during the 8–14 day period. On the contrary, Nannochloropsis sp. displayed a reduced growth rate at 2 mg L⁻¹ of Al concentration. Both species showed an Al removal efficiency of up to 98–99.7 %. The removal efficiency of two algae was abundance-independent in the present study. Our findings indicated that both microalgae species offer great potential for treating Al-contaminated water, with Scenedesmus sp. standing out for tolerance and removal efficiency, while Nannochloropsis sp. excels in absorbing Al at lower concentrations.

Enhancing iron bioavailability through iron-enriched yeast offers a promising nutritional solution. This study explores the sustainable production of iron-enriched yeast using soybean, corn, and wheat bran hydrolysates as low-cost culture media in submerged fermentation. Culture mediums were supplemented with 15 mg L⁻¹ of Fe⁺². Iron-yeast production was successful using starchy hydrolysates due to their rich composition. Soybean bran hydrolysate achieved the highest biomass production (7.9 g L⁻¹ dry cell), corn bran hydrolysate accomplished the largest iron incorporation (3.18 mg of iron/gram of dry cell); while supplemented wheat hydrolysate attained the greatest yield (2.58 ± 0.68 g/g). This research showed high potential on the production of iron-enriched yeast biomass from starchy hydrolysates, and the potential production of health and food products through sustainable production methods.

Our research has revealed that the nitrogen doping configuration has a significant impact on the absorption properties and band gap of nitrogen doped graphene quantum dots (NGQDs). By analyzing the composition and character of optical transitions, we have observed that nitrogen doping causes a redistribution of oscillator strength between significant peaks and the emergence of new optical features. These changes lead to broken molecular orbital degeneracies, optical peak splitting, and activation of dark states in the visible to near-infrared (NIR) region. These findings shed light on the mechanisms that govern alterations in the spectral properties of NGQDs within the visible and near-infra red (NIR) absorption bands. Furthermore, selective manipulation of optoelectronic properties via distinct N-doping patterns could pave the way for the development of novel optoelectronic nanodevices and functional materials.

Plastics are the most utilized material in every commercial or domestic sector. The extensive use of plastics can lead to the generation of byproducts, and microplastics are among them. The introduction and integration of microplastics into the environment have severe effects on both living and non-living entities. Moreover, extracting and removing microplastics from the environment presents significant challenges. In this context, recognizing quantity-wise removal becomes a major task. Until now, a universally established method for quantitative measurement has not been established. Various units, such as items/m³, particles/kg, and mg/kg, have been utilized based on their suitability. However, these units come with their own merits and demerits. To address this, the article focuses on filling the gaps in the utilization and generalization of units for further studies. Using the mg/kg unit for measuring microplastics in collected samples can be an appropriate method for analysing the quantity of microplastics.

Heavy metal contamination in river water is a result of anthropogenic sources like industrial waste, tanneries, used fertiliser, and sewage discharge. Bioaccumulation and toxicity of heavy metals are alarming concerns for the natural carp breeding ground of the one and only river Halda of Bangladesh. Seven heavy metals (Fe, Mn, Cu, Co, Ni, Zn, and Cr (VI)) were assessed in this study following standard methods by gathering data from 36 sampling points that are situated along the area between the origin of Halda and Kalurghat confluence point of Halda and Karnofuli. An atomic absorption spectrophotometer was used for the measurement of the heavy metals, and the correlation between the parameters was determined using principal component analysis (PCA). The concentration of heavy metals ranged from 0.316 to 3.216 mg/L for Fe, 0.023–0.236 mg/L for Mn, 0.022–0.044 mg/L for Cu, 0.022–0.051 mg/L for Co, 0.002–0.008 mg/L for Ni, 0.037–0.282 mg/L for Zn, and 0.013–0.146 mg/L for Cr (VI), respectively. Cu and Mn values in some points were above the permissible limit, but other metal contents were within the permissible limit.

Recent advances in sensing technologies address environmental pollution by enabling rapid and sensitive contaminant detection. Among these, porphyrin- and graphene-based electrochemical sensors stand out due to their high surface area, superior conductivity, and analyte sensitivity. Graphene, a two-dimensional carbon nanomaterial, and porphyrins, macrocyclic organic compounds with exceptional electrochemical properties, combine to create effective sensors for detecting various pollutants, including organic pollutants, biological contaminants, and heavy metals. Integrating graphene with porphyrins enhances electron transfer kinetics, selectivity, and stability, making them ideal for environmental monitoring applications. This paper discusses the principles of material selection, sensor design, and fabrication methods for these sensors. It highlights recent advancements in detecting specific pollutants, such as biological contaminants (viruses and bacteria), organic pollutants (pesticides, phenols, and polycyclic aromatic hydrocarbons), and heavy metals (Pb, Hg, and Cd). Additionally, it addresses the challenges and future prospects of these sensors, focusing on improving sensitivity, selectivity, stability, and reproducibility, as well as their integration with portable and wearable devices for on-site monitoring. This review provides valuable insights into the current state and potential applications of porphyrin- and graphene-based electrochemical sensors in pollution management and environmental monitoring.

Despite the abundant nutrients that could be reutilized in swine wastewater, inadequate wastewater management leads to excessive metals and organic matter, causing environmental impacts on aquatic and terrestrial ecosystems. In this study, we recycled waste pumice and oyster shells for the cost-effective treatment and reclamation of swine wastewater. The toxicity of the treated wastewater was assessed using the soil nematode Caenorhabditis elegans and Chinese cabbage Brassica rapa chinensis. Our findings showed significant removal of suspended solids, biochemical oxygen demand, chemical oxygen demand, total phosphorus, and heavy metals (As, Cu, Ni, and Zn) from the swine wastewater after treatment with pumice and oyster shells. Moreover, untreated wastewater significantly inhibited the germination of Chinese cabbage, a trend that was reversed in treated wastewater. Both treated and untreated swine wastewater stimulated the growth of Chinese cabbage. Additionally, untreated swine wastewater exhibited high toxicity to the growth and reproduction of C. elegans after 72 hours of exposure, whereas treated wastewater showed notably reduced toxicity. The recycled pumice and oyster shells significantly induced growth and showed no toxicity in Chinese cabbage. These results suggest that pumice and oyster shell waste can effectively reduce environmental toxicity in raw swine wastewater, offering a cost-effective wastewater treatment solution for small-scale pig farms.

The use of high-value biomass resources for the green and renewable synthesis of biodiesel is an effective strategy for reducing greenhouse gas emissions and providing a sustainable alternative to depleting fossil fuels. In the present study, Nannorrhops ritchieana, a highly promising seed oil feedstock with 25 % oil content, was evaluated for biodiesel production using zinc oxide nanoparticles (ZnONPs) synthesized with aqueous leaf extract of Alternanthera pungens. The highest biodiesel yield of 95 % was achieved under optimum reaction conditions: a methanol to oil molar ratio of 7: 1, catalyst loading of 0.18 wt%, a reaction temperature of 80 °C, and a reaction time of 180 min. Analysis of the synthesized ZnONPs revealed its pure, thermally stable and nanoscale nature, with an average particle size of 22 nm. Gas chromatography mass spectroscopy (GC-MS) analysis identified distinct peaks of methyl esters, with 9-Octadecenoic acid, (Z)-methyl ester having the highest concentration. The fuel properties of the biodiesel— density (0.912 kg/m³), viscosity (6.45 mm²/s), flash point (93 °C), cloud (-7 °C), and pour point (-10 °C)— aligned with international fuel standards.

The synthesis of nanoparticles using sustainable plant-assisted techniques offers great potential for various applications, including biomedicine and environmental remediation. The methods have numerous benefits in terms of safety, environmental sustainability, and resource efficiency. However, maintaining standardization and reproducibility in these synthesis processes remains a critical challenge. Factors such as variations in plant species, growth conditions, and extraction methods have been identified as contributing factors to inconsistencies in the properties and performance of nanoparticles. Furthermore, the use of diverse experimental protocols and analytical techniques complicates the comparison and validation of data across investigations. Standardization protocols and advances in analytical methods, such as standardized characterization methodologies and data reporting practices, ensure reproducibility and facilitate meaningful comparisons between research. This review examines the current level of sustainable plant-assisted nanoparticle synthesis, focusing on the barriers to standardization and reproducibility, and proposes future directions to enhance result reliability, promote consistency and reproducibility, enable comparisons, foster collaboration, and advance industrial applications of plant-assisted nanoparticles through process standardization.

Microplastics (MPs) presence in soil and aquatic ecosystems has become a serious concern over the last decade. Due to their small size and physical and chemical characteristics, MPs have potential risks of bio-accumulation in aquatic and soil ecosystems. The accumulated MPs may have various adverse effects on the different components of the ecosystem. MPs may alter the physical properties of soil, including permeability, water retention, and soil structure. Apart from that, MPs may also affect plant growth, soil-dwelling species, microbial populations, and nutrient-cycling processes. Therefore, understanding MPs from source to sink is necessary. Hence, we have comprehensively reviewed the potential toxicity of MPs in soil and aquatic ecosystems. The review also discusses different methodologies used for quantification and detection. The difference in methods used for quantification and detection may significantly affect overall toxicity assessment. This review aims to provide a detailed understanding of MPs in soil and aquatic ecosystems for upcoming research work.