Sustainable hydrogen production via microalgae: Technological advancements, economic indicators, environmental aspects, challenges, and policy implications.

Hydrogen has emerged as an alternative energy source to meet the increasing global energy demand, depleting fossil fuels and environmental issues resulting from fossil fuel consumption. Microalgae-based biomass is gaining attention as a potential source of hydrogen production due to its green energy carrier properties, high energy content, and carbon-free combustion. This review examines the hydrogen production process from microalgae, including the microalgae cultivation technological process for biomass production, and the three main routes of biomass-to-hydrogen production: thermochemical conversion, photo biological conversion, and electrochemical conversion. The current progress of technological options in the three main routes is presented, with the various strains of microalgae and operating conditions of the processes. Furthermore, the economic and environmental perspectives of biomass-to-hydrogen from microalgae are evaluated, and critical operational parameters are used to assess the feasibility of scaling up biohydrogen production for commercial industrial-scale applications. The key finding is the thermochemical conversion process is the most feasible process for biohydrogen production, compared to the pyrolysis process. In the photobiological and electrochemical process, pure hydrogen can be achieved, but further process development is required to enhance the production yield. In addition, the high production cost is the main challenge in biohydrogen production. The cost of biohydrogen production for direct bio photolysis it cost around $7.24 kg-1; for indirect bio photolysis it costs around $7.54 kg-1 and for fermentation, it costs around $7.61 kg-1. Therefore, comprehensive studies and efforts are required to make biohydrogen production from microalgae applications more economical in the future.

Mangrove health along the hyper-arid southern Red Sea coast of Saudi Arabia.

Changes in land use and land cover have severely influenced the sustainability of mangrove vegetation, especially in the hyper-arid, hyper-saline Red Sea coastal waters of Saudi Arabia. The present study investigates the effect of effluents released from an adjoining shrimp farm on the sustainability of a nearby mangrove woodland during operation and after closure of the farm. In addition, the consequences of dredging activities to fill coastal waters for land reclamation to develop a mega seaport at Jazan Economic City are explored. A band image-difference algorithm was applied to Landsat 5 Thematic Mapper and Landsat 08 Operational Land Imager satellite images obtained on different dates, which revealed a prominent vigour boom in the mangrove forest while the shrimp farm operated but a gradual decrease in vigour after its closure. During the investigation time frame of 2016 and 2017, spectral vegetation analysis of Sentinel-2A satellite images highlighted a strong negative correlation between dredging operations for seaport construction and the adjacent fragile mangrove forest. Dredging operations were responsible for a reduction of 19.30% in the Normalized Difference Vegetation Index, 27.5% in the Leaf Area Index, and 19.0% in the Optimized Soil Adjusted Vegetation Index. The results clearly show the potential application of spectral vegetation indices in the monitoring and analysis of anthropogenic impacts on coastal vegetation. We suggest strong management efforts for monitoring, assessing, and regulating measures to offset the negative trends in the sustainability of mangroves in Red Sea coastal regions.

Transition metal-based nanoparticles as potential antimicrobial agents: recent advancements, mechanistic, challenges, and future prospects.

Bacterial transmission is considered one of the potential risks for communicable diseases, requiring promising antibiotics. Traditional drugs possess a limited spectrum of effectiveness, and their frequent administration reduces effectiveness and develops resistivity. In such a situation, we are left with the option of developing novel antibiotics with higher efficiency. In this regard, nanoparticles (NPs) may play a pivotal role in managing such medical situations due to their distinct physiochemical characteristics and impressive biocompatibility. Metallic NPs are found to possess extraordinary antibacterial effects that are useful in vitro as well as in vivo as self-modified therapeutic agents. Due to their wide range of antibacterial efficacy, they have potential therapeutic applications via diverse antibacterial routes. NPs not only restrict the development of bacterial resistance, but they also broaden the scope of antibacterial action without binding the bacterial cell directly to a particular receptor with promising effectiveness against both Gram-positive and Gram-negative microbes. This review aimed at exploring the most relevant types of metal NPs employed as antimicrobial agents, particularly those based on Mn, Fe, Co, Cu, and Zn metals, and their antimicrobial mechanisms. Further, the challenges and future prospects of NPs in biological applications are also discussed.

SARS-CoV-2 removal by mix matrix membrane: A novel application of artificial neural network based simulation in MATLAB for evaluating wastewater reuse risks.

The COVID-19 outbreak led to the discovery of SARS-CoV-2 in sewage; thus, wastewater treatment plants (WWTPs) could have the virus in their effluent. However, whether SARS-CoV-2 is eradicated by sewage treatment is virtually unknown. Specifically, the objectives of this study include (i) determining whether a mixed matrixed membrane (MMM) is able to remove SARS-CoV-2 (polycarbonate (PC)-hydrous manganese oxide (HMO) and PC-silver nanoparticles (Ag-NP)), (ii) comparing filtration performance among different secondary treatment processes, and (iii) evaluating whether artificial neural networks (ANNs) can be employed as performance indicators to reduce SARS-CoV-2 in the treatment of sewage. At Shariati Hospital in Mashhad, Iran, secondary treatment effluent during the outbreak of COVID-19 was collected from a WWTP. There were two PC-Ag-NP and PC-HMO processes at the WWTP targeted. RT-qPCR was employed to detect the presence of SARS-CoV-2 in sewage fractions. For the purposes of determining SARS-CoV-2 prevalence rates in the treated effluent, 10 L of effluent specimens were collected in middle-risk and low-risk treatment MMMs. For PC-HMO, the log reduction value (LRV) for SARS-CoV-2 was 1.3-1 log10 for moderate risk and 0.96-1 log10 for low risk, whereas for PC-Ag-NP, the LRV was 0.99-1.3 log10 for moderate risk and 0.94-0.98 log10 for low risk. MMMs demonstrated the most robust absorption performance during the sampling period, with the least significant LRV recorded in PC-Ag-NP and PC-HMO at 0.94 log10 and 0.96 log10, respectively.

Exploring the potential of metal and metal oxide nanomaterials for sustainable water and wastewater treatment: A review of their antimicrobial properties.

Metallic nanoparticles (NPs) are of particular interest as antimicrobial agents in water and wastewater treatment due to their broad suppressive range against bacteria, viruses, and fungi commonly found in these environments. This review explores the potential of different types of metallic NPs, including zinc oxide, gold, copper oxide, and titanium oxide, for use as effective antimicrobial agents in water and wastewater treatment. This is due to the fact that metallic NPs possess a broad suppressive range against bacteria, viruses, as well as fungus. In addition to that, NPs are becoming an increasingly popular alternative to antibiotics for treating bacterial infections. Despite the fact that most research has been focused on silver NPs because of the antibacterial qualities that are known to be associated with them, curiosity about other metallic NPs as potential antimicrobial agents has been growing. Zinc oxide, gold, copper oxide, and titanium oxide NPs are included in this category since it has been demonstrated that these elements have antibacterial properties. Inducing oxidative stress, damage to the cellular membranes, and breakdowns throughout the protein and DNA chains are some of the ways that metallic NPs can have an influence on microbial cells. The purpose of this review was to engage in an in-depth conversation about the current state of the art regarding the utilization of the most important categories of metallic NPs that are used as antimicrobial agents. Several approaches for the synthesis of metal-based NPs were reviewed, including physical and chemical methods as well as "green synthesis" approaches, which are synthesis procedures that do not involve the employment of any chemical agents. Moreover, additional pharmacokinetics, physicochemical properties, and the toxicological hazard associated with the application of silver NPs as antimicrobial agents were discussed.

Simultaneous microbial electrochemical degradation of methyl orange and bioelectricity generation using coculture as anode inoculum in a microbial fuel cell.

Methyl Orange, an azo dye, is a widely used colouring agent in the textile industry. The study aimed to investigate the efficiency of bioremediating bacteria in degrading methyl orange. Escherichia coli (E. coli), a Methyl Orange-degrading bacterium, was isolated from cow dung and its biochemical properties were analysed using 16S rRNA sequencing, and MALDI-TOF MS. A pre-cultured strain of Pseudomonas aeruginosa was co-cultured with E. coli in 1:1 ration in a microbial fuel cell (MFC) for simultaneous electricity production and methyl orange degradation. The degradation was combined with biological wastewater treatment at varying Methyl Orange concentrations, and the electrochemical characteristics were analysed through polarisation study, cyclic voltammetry, and electrochemical impedance spectroscopy. The impact of parameters such as anolyte pH, dye concentration, incubation time, and substrate concentrations were also studied. This study confirmed E. coli as an effective methyl orange degrading bacteria with a maximum % degradation efficiency of 98% after 48 h incubation at pH 7.0. The co-culture of isolated microorganisms at 250 mg/L of methyl orange concentration showed a maximum power density 6.5 W/m3. Further, anode modification with Fe2O3 nanoparticles on the anode surface enhanced power production to 11.2 W/m3, an increase of 4.7 W/m3.

Marine environment and maritime safety assessment using Port State Control database.

Port State Control (PSC) is the inspection of foreign ships in national ports assists in the removal of substandard ship commerce from the global sea and ensures that no ship poses a threat to maritime safety and the marine environment. When a clear ground is discovered during an inspection, the inspector has the authority to detain the ship until the flaws are corrected in order to assure safety and reduce pollution hazards. This paper adopted a traditional literature review method using the selected six (6) years data from the inspections conducted by maritime authorities from 2016 to 2021 and incorporate with qualitative and quantitative analysis to ascertain the influence of each risk factor on the number of arrests, including the relationship between risk factors and the type of detain deficiency, which is a critical part of the study. This study's findings provide important insights into how to facilitate an effective way in selecting the ship to be inspected, followed by identifying the ship's risk profile and designing the inspection area, which plays a critical role in assisting the inspector in terms of time efficient and effective inspection (especially for the ships, which have a short duration at berth) during inspection to further strengthen maritime safety, ship's safety, seafarers' health and marine environmental protection.

Critical role of Hyssop plant in the possible transmission of SARS-CoV-2 in contaminated human Feces and its implications for the prevention of the virus spread in sewage.

The significant issue affecting wastewater treatment is human faeces containing SARS-CoV-2. SARS-CoV-2, as a novel coronavirus, has expanded globally. While the current focus on the COVID-19 epidemic is rightly on preventing direct transmission, the risk of secondary transmission via wastewater should not be overlooked. Many researchers have demonstrated various methods and tools for preventing and declining this virus in wastewater treatment, especially for SARS-CoV-2 in human faeces. This research reports two people tested for 30 d, with written consent, at Mosa-Ebne-Jafar Hospital of Quchan, Iran, from September 1st to October 9th, 2021. The two people's conditions are the same. The Hyssop plant was used, which boosts the immune system's effectiveness and limonene, rosemary, caffeic acids and flavonoids, all biologically active compounds in this plant, cause improved breathing problems, colds, and especially for SARS-CoV-2. As a result, utilising the Hyssop plant can help in reducing SARS-CoV-2 in faeces. This plant's antioxidant properties effectively reduce SARS-CoV-2 in faeces by 30%; nevertheless, depending on the patient's condition. This plant is also beneficial for respiratory and digestive health.

Model analysis on effect of temperature on the solubility of recycling of Polyethylene Terephthalate (PET) plastic.

The massive increase in the use of PET plastic bottles has raised the challenge of accumulated waste plastics disposal and its related environmental concerns. Reusing this plastic waste through a solvent-based recycling process seems to be an eco-friendly solution for eliminating waste plastic and converting them into high quality products. The selection of solvent with its temperature requirement for the dissolution of polymeric materials is crucial in the solvent-based recycling process. Therefore, an innovative MATLAB program named HSPs-TPT was designed and constructed in this work to evaluate the dissolving power of solvents. Through this program, the solubility of the waste PET polymer was examined in thirteen (13) different solvents at different temperatures. As a results, the degree of waste PET polymer dissolution in the solvents was presented as the polymer-solvent solubility diagram, which provided the information about the relative energy difference (RED) change with the temperature rise. The program also provided the temperature range effective for the dissolution of PET by indicating the minimum and maximum solubility point for each solvent, which was further validated by the experimental data found in the literature. The proposed MATLAB program can numerically analyse the solubility of a polymer in different solvents in a short time for the recycling process and fabrication of different value-added plastic products such as polymer monoliths and membrane filters.

An approach to removing COD and BOD based on polycarbonate mixed matrix membranes that contain hydrous manganese oxide and silver nanoparticles: A novel application of artificial neural network based simulation in MATLAB.

This study aimed to determine the efficacy of novel ultrafiltration and mixed matrix membrane (MMM) composed of hydrous manganese oxide (HMO) and silver nanoparticles (Ag-NPs) for the removal of biological oxygen demand (BOD) and chemical oxygen demand (COD). In the polycarbonate (PC) MMM, the weight percent of HMO and Ag-NP has been increased from 5% to 10%. A neural network (ANN) was used in this study to compare PC-HMO and Ag-NP. MMM was evaluated in combination with HMO and Ag-NP loadings in order to assess their effects on pure water flux, mean pore size, porosity, and efficacy in removing BOD and COD. HMO and Ag-NPs can decrease membrane porosity in the casting solution while increasing mean pore size. According to the study's findings, the artificial neural network model appears to be highly appropriate for predicting the removal of BOD and COD. To develop a successful model, a suitable input dataset was selected, which consisted of BOD and COD. An ideal model architecture for MMM was proposed based on an optimal number of hidden layers (2 layers) and neurons (5-8 neurons). Experiments and predicted data show a strong correlation between the developed models. BOD was predicted with an excellent R2 and a low root mean square error (RMSE) of 0.99 and 0.05%, respectively, while COD was predicted with an excellent R2 and a low RMSE of 0.99 and 0.09%, respectively. Based on the results, Ag-NP was found to be an excellent candidate for the preparation of MMMs as well as convenient for the removal of BOD and COD from polluted water sources.

Membrane based reactors for sustainable treatment of Coronopus didymus L. by developing Iodine doped potassium oxide Catalyst under Dynamic conditions.

Green nano-technology together with the availability of eco-friendly and alternative sources are the promising candidates to combat environment deteriorations and energy clutches globally. The current work focuses on the synthesis and application of newly synthesized nano catalyst of Iodine doped Potassium oxide I (K2O) for producing sustainable biodiesel from novel non-edible seed oils of Coronopus didymus L. using membrane based contactor to avoid emulsification and phase separation issues. Highest biodiesel yield (97.03%) was obtained under optimum conditions of 12:1 methanol to oil ratio, reaction temperature of 65 °C for 150 min with the 1.0 wt% catalyst concentration. The lately synthesized, environment friendly and recyclable Iodine doped Potassium oxide K (IO)2 catalyst was synthesized via chemical method followed by characterization via advanced techniques including EDX, XRD, FTIR and SEM analysis. The catalyst was proved to be stable and efficient with the reusability of five times in transesterification reaction. These analysis have reported the sustainability, stability and good quality of biodiesel from seed oil of Coronopus didymus L. using efficient Iodine doped potassium oxide catalyst. Thus, non-edible, environment friendly and novel Coronopus didymus L. seeds and their extracted oil along with Iodine doped potassium oxide catalyst seems to be highly affective, sustainable and better alternative source to the future biodiesel industry. Also, by altering the reaction equilibrium and lowering the purification phases of the process, these studies show the potential of coupling transesterification and a membrane contactor.

Polymeric membranes for environmental remediation: A product space model perspective.

The development of polymeric membranes from polymers such as polystyrene (PS), polyvinylchloride (PVC), and their associated family has brought great momentum to the environmental remediation universe, mainly due to their surprisingly diverse and multi-purpose nature. Their usage has surged 20 times in the last half-century and is likely to double again in the coming 20 years. As a result, the polymeric materials economy and commercialization of research become increasingly important as a possible option for a country to boost prosperity while decreasing its reliance on limited raw resources and mitigating negative externalities. This transformation demands a systematic strategy, which involves progress beyond improving the existing models and building new avenues for collaboration. In this work, a sophisticated system, i.e., product space model (PSM), has been presented, explicitly appraising the opportunity space for United Kingdom, Italy, Poland, India, Canada, Indonesia, Brazil, Saudi Arabia, Russia and Colombia for their potential future industrialization and commercialization of polymeric membranes for environmental remediation. The results revealed that UK, Italy, Poland and India are at advantageous positions owing to their close proximity of (distance<2) and their placement in Parsimonious policy, which is the most desired quadrant of Policy Map of PSM, Canada and Indonesia have medium level opportunities, while Russia and Saudi Arabia have opportunities with more challenges to fully exploit the unexploited polymers products in terms of membranes for environmental remediation and prove favorable for export diversification, sustainable economic growth, and commercialization.

Scientometric analysis and scientific trends on microplastics research.

In recent years, the environmental pollution of microplastics has attracted much attention. To date, there have been a lot of researches on microplastics and a series of studies published. In this study, by bibliometric analysis method to evaluated the development and evolution on microplastics research trends and hot spots. A total of 2872 literature information was collected from the Web of Science (2004-2020), which was used for bibliometric visual analysis by CiteSpace. It was possible to see the contributing countries, institutions, authors, keywords, and future study directions in the microplastics sectors by looking at the visual representation of the results. (1) Since 2004, scientific advancements in this sector have advanced significantly, with a significant increase in speed since 2012. (2) China and the United States are the world's leading researchers in microplastics. (3) The study of microplastics was multidisciplinary, comprising researchers from the fields of ecology, chemistry, molecular biology, environmental science, and oceanography. (4) In recent years, researchers have concentrated their attention on the distribution and toxicity of microplastics in the environment, as well as their coupled pollution with heavy metal contaminants. In conclusion microplastics study in environmental science has become increasingly popular in recent years. Topics include dispersion, toxicity, and coupled pollution with heavy metal pollutants. Researchers in a wide range of fields are involved in microplastics research. Furthermore, policies and regulations about microplastics in global were summarized, and membrane technology has potential to remove microplastics from water. The above findings help to clearly grasp the content and development trend of microplastics research, point out the future research direction for scholars, and promote microplastics research and pollution prevention and control.

Phytochemical characterization, and antioxidant and antimicrobial activities of essential oil from leaves of the common sage Salvia officinalis L. from Abha, Saudi Arabia.

Background: The composition and activities of essential oil of common sage from Saudi Arabia have not yet been reported. Objectives: To analyze the composition and antibacterial and antioxidant activities of essential oil from leaves of the common sage Salvia officinalis L. from Abha, Saudi Arabia. Methods: Essential oil was extracted from the leaves of S. officinalis by hydrodistillation, and its composition was analyzed using gas chromatography and mass spectrometry. Phenolics and flavonoids were determined using gallic acid and quercetin standards. Antioxidant activity was determined using a 2,2-diphenyl-1-picrylhydrazyl radical scavenging method. Activity against various gram-positive and gram-negative bacteria was determined by disk diffusion and microdilution. Results: The yield of essential oil was 3.24 ± 0.55% (w/dry weight). Major compounds identified were camphor (20.3%), 1,8-cineole (15.0%), α-thujone (14.9%), viridiflorol (9.9%), carvone (6.2%), and ß-thujone (5.7%). Phenolic content was 134.3 ± 17.61 µg/mL and flavonoid content was 119.5 ± 18.75 µg/mL. Antioxidant IC50 was 970 ± 5.5 µg/mL. The highest gram-positive antibacterial activity was for Bacillus subtilis and the highest gram-negative activity was for Escherichia coli. Minimum inhibitory concentrations ranged from 62.2 ± 3.9 to 1398.1 ± 50.7 µg/mL for gram-positive bacteria and from 323.4 ± 69.5 to 968.4 ± 120.6 µg/mL for gram-negative bacteria. Minimum bactericidal concentrations ranged from 120.3 ± 7.6 to 1387.4 ± 161.8 µg/mL for gram-positive bacteria and from 386 ± 8.3 to 1225.2 ± 100.9 µg/mL for gram-negative bacteria. Conclusions: Essential oil of S. officinalis L. from Abha, Saudi Arabia, showed compositional, antioxidant, and antibacterial properties generally consistent with essential oil of S. officinalis L. from other locations as reported in the literature.

Recrystallization techniques for the synthesis of ZnO nanorods: an in situ process for carbon doping and enhancing the dispersion concentration of ZnO nanorods.

Zinc acetate is recrystallized as lumber-shaped tetragonal rods by a novel recrystallization technique. Subsequently, the recrystallized zinc acetate is converted into ZnO nanorods in a glass vial by the simplest and cheapest method without utilizing any expensive instrumentation. Carbon is doped in ZnO nanorods during the preparation ZnO nanorods without any extra steps, chemicals, or effort. The carbon-doped ZnO nanorods can be dispersed in a solvent at very high concentrations and are also stable for a very long time, which are comparatively higher than those of the other existing ZnO nanoparticles. The higher dispersion concentration and higher stability of ZnO nanoparticles are explained by a scheme that demonstrates the suspending mechanism of the ZnO nanoparticles at higher concentrations with higher stabilities in a solvent through the anchoring groups of carbon. No materials are used for surface modification; no surface coatings, ionic materials, or pH controlling materials are used to increase the dispersion concentration and stability. This is the first observation of the doped carbon playing a significant role in the dispersion of ZnO nanoparticles at higher concentrations by withholding them in the solvent. Therefore, doped carbon at the surface of ZnO nanoparticles prevents the self-aggregation of ZnO nanoparticles in the solution phase by interfacial barrier layers among ZnO nanorods and interfacial interactive layer between ZnO nanorod and solvent.

Alignment of Carbon Nanotubes in Carbon Nanotube Fibers Through Nanoparticles: A Route for Controlling Mechanical and Electrical Properties.

This is the first study that describes how semiconducting ZnO can act as an alignment agent in carbon nanotubes (CNTs) fibers. Because of the alignment of CNTs through the ZnO nanoparticles linking groups, the CNTs inside the fibers were equally distributed by the attraction of bonding forces into sheetlike bunches, such that any applied mechanical breaking load was equally distributed to each CNT inside the fiber, making them mechanically robust against breaking loads. Although semiconductive ZnO nanoparticles were used here, the electrical conductivity of the aligned CNT fiber was comparable to bare CNT fibers, suggesting that the total electron movement through the CNTs inside the aligned CNT fiber is not disrupted by the insulating behavior of ZnO nanoparticles. A high degree of control over the electrical conductivity was also demonstrated by the ZnO nanoparticles, working as electron movement bridges between CNTs in the longitudinal and crosswise directions. Well-organized surface interface chemistry was also observed, which supports the notion of CNT alignment inside the fibers. This research represents a new area of surface interface chemistry for interfacially linked CNTs and ZnO nanomaterials with improved mechanical properties and electrical conductivity within aligned CNT fibers.