Harmful Materials Research Articles

Tight Junctions of the Neurovascular Unit.

The homeostatic balance of the brain and retina is maintained by the presence of the blood-brain and inner blood-retinal barrier (BBB/iBRB, respectively) which are highly specialized barriers. Endothelial cells forming the lining of these blood vessels are interconnected by the presence of tight junctions which form the BBB and iBRB. These tight junctions, formed of numerous interacting proteins, enable the entry of molecules into neural tissues while restricting the entry of harmful material such as anaphylatoxins, bacteria and viruses. If the tight junction complex becomes dysregulated due to changes in expression levels of one or more of the components, this can have detrimental effects leading to brain and retinal pathology.

Effects of three iron material treatments on hydrogen sulfide release from anoxic sediments.

In eutrophic coastal regions, hydrogen sulfide (H2S) is a harmful material released from sediments under anoxic conditions. To suppress its release, we conducted laboratory experiments and assessed the impacts of treatment with three iron materials (Fe, Fe2O3, and FeOOH), focusing on the area-specific H2S release rate. These materials qualitatively exhibited a substantial suppression of H2S release; however, smaller treatment levels (<150 mmol m-2) were ineffective. FeOOH exhibited the best performance, followed by Fe2O3, and Fe. These differences were likely caused by variations in the oxidation or reduction potential of the materials and their reaction rates with H2S. A simplified model suggested that the required minimum Fe2+ concentration was determined using the H2S diffusivity, reaction rate constant, and treatment penetration depth. As the former two are physical constants, the latter must control the H2S release rate. Iron materials were experimentally confirmed to persist for over three weeks, and the effective treatment level was theoretically estimated as being capable of suppressing H2S release for more than a year. Our results will contribute to coastal environmental management and particularly benefit port authorities who manage enclosed and eutrophicated harbors and navigation channels where slag application should be avoided.

Phytoremediation of Toxic Metals: A Sustainable Green Solution for Clean Environment

Contamination of aquatic ecosystems by various sources has become a major worry all over the world. Pollutants can enter the human body through the food chain from aquatic and soil habitats. These pollutants can cause various chronic diseases in humans and mortality if they collect in the body over an extended period. Although the phytoremediation technique cannot completely remove harmful materials, it is an environmentally benign, cost-effective, and natural process that has no negative effects on the environment. The main types of phytoremediation, their mechanisms, and strategies to raise the remediation rate and the use of genetically altered plants, phytoremediation plant prospects, economics, and usable plants are reviewed in this review. Several factors influence the phytoremediation process, including types of contaminants, pollutant characteristics, and plant species selection, climate considerations, flooding and aging, the effect of salt, soil parameters, and redox potential. Phytoremediation’s environmental and economic efficiency, use, and relevance are depicted in our work. Multiple recent breakthroughs in phytoremediation technologies are also mentioned in this review.

The reality of adolescent girls' exposure to the dangers of the digital world in Saudi society: A study applied to a sample of middle school students in the city of Riyadh: واقع تعرض المراهقات لمخاطر العالم الرقمي في المجتمع السعودي: دراسة مطبقة على عينة من طالبات المرحلة المتوسطة في مدينة الرياض

This study aimed to identify the reality of adolescent girls' exposure to the dangers of the digital world according to the classification of the UNICEF organization and to reveal the most dangerous applications for them. This study relied on the method of social survey through the sample using the questionnaire tool, and the study sample reached (402) single female students Medium in the city of Riyadh, using stratified random sampling. The results of the study revealed that content-related risks are among the most common types of risks that adolescent girls face in the digital world, followed by communication risks and then behavioral risks. The results also showed that among the applications in which adolescent girls are most exposed to the dangers of the digital world (Instagram - Twitter - Snapchat), In terms of usage, YouTube ranked first in terms of usage, followed by Snapchat, Instagram, WhatsApp, Twitter, Tik Tok, then PUBG and Fortnite. The study recommended the need to establish a specialized unit affiliated to the Communications and Information Technology Commission, which includes a number of specialists in the social, psychological and cybersecurity fields. It also includes visual and print media and celebrities of social networking sites who have an impact on the category of children and adolescents. The study also recommended the need to focus the efforts of the committee. To legalize the ethical content of information technology on the most popular websites and applications in the digital world, such as (Twitter, Instagram), by intensifying censorship and working to reduce the availability of harmful and inappropriate materials on these sites.

Photocatalytic Air Purification Using Functional Polymeric Carbon Nitrides.

The techniques for the production of the environment have received attention because of the increasing air pollution, which results in a negative impact on the living environment of mankind. Over the decades, burgeoning interest in polymeric carbon nitride (PCN) based photocatalysts for heterogeneous catalysis of air pollutants has been witnessed, which is improved by harvesting visible light, layered/defective structures, functional groups, suitable/adjustable band positions, and existing Lewis basic sites. PCN‐based photocatalytic air purification can reduce the negative impacts of the emission of air pollutants and convert the undesirable and harmful materials into value‐added or nontoxic, or low‐toxic chemicals. However, based on previous reports, the systematic summary and analysis of PCN‐based photocatalysts in the catalytic elimination of air pollutants have not been reported. The research progress of functional PCN‐based composite materials as photocatalysts for the removal of air pollutants is reviewed here. The working mechanisms of each enhancement modification are elucidated and discussed on structures (nanostructure, molecular structue, and composite) regarding their effects on light‐absorption/utilization, reactant adsorption, intermediate/product desorption, charge kinetics, and reactive oxygen species production. Perspectives related to further challenges and directions as well as design strategies of PCN‐based photocatalysts in the heterogeneous catalysis of air pollutants are also provided.

Biosynthesis of Zinc oxide nanoparticles using Bergenia ciliate aqueous extract and evaluation of their photocatalytic and antioxidant potential

The present study was aimed to carry out a novel, non-toxic, cost-effective, and green way to prepare Zinc oxide nanoparticles (ZnONPs) using Bergenia ciliate extract as both reducing and capping agents without any harmful material. The bioreduced ZnONPs were characterized using powder X-ray diffraction (XRD), ultraviolet–visible spectroscopy (UV–Vis spectroscopy), Field Emission Scanning electron microscopy (FE-SEM). The crystal structure and phase purity of the synthesized ZnONPs carried by PXRD analysis showed the hexagonal symmetry of ZnONPs. The morphology as determined by FE-SEM analysis revealed that the nanoparticles were having truncated octahedron morphology and the particulate size within 23–59 nm. The elemental composition was determined by EDAX analysis. The optical properties of ZnONPs as determined by UV–Vis spectroscopy shows the maximum absorption at 355 nm. About 82% degradation of methylene blue dye was achieved within the time of 52 min on exposure to ZnONPs in sunlight. Further, the ZnONPs showed good antioxidant activity by using the DPPH assay. The present investigation sheds light on the synthesis of ZnONPs by utilizing a green synthetic approach involving leaf extract of Bergenia ciliata for the first time. The current study is an attempt to describe an effective, simple, and eco-friendly method of ZnONPs synthesis and to evaluate its potential for various industrial and environmental applications.

Review of research and development on pyrolysis process

Now a days disposal of plastic, rubber and Aluminium are big problem. Burning of agricultural wastes in open field is also gives serious threat to the environment. But they can be converted into useful products like heat, power, oil, gas, and biochar using Pyrolysis process. Many research works have been carried out to convert the harmful materials into useful by products. In this paper, pyrolyser used by various researchers are reviewed under the topics the various raw materials, temperature obtained and application. Some of the modified pyrolysers are also reviewed.

Study on bio-fish extract and cultivation dates to improve production of flax (Linum usitatissimum) in Omar-Mukhtar area, Libya

Flax seeds (Linum usitatissimum L.) are known to be very useful source of fiber and nutrition soil; also boi-fish extract has shown to be a from of organic fertilizer of very high quality. Our objective is to contribute to the research effort to produce healthy, safe and organic crops, while saving the soil from being damaged and the environment for any harmful materials. Therefore, we conducted study in Omar-Mukhtar Al-Jabal Al-Akhdar district in northeastern Libya, in the growing seasons of 2016–17 and 2017–18 in to examine the effect of marine bio-fish extract as organic fertilization and of different cultivation dates on improving yields for three flax varieties cultivated. The experiment was laid under split-split plot design utilizing three-factor complete randomized block design organized with three replicates. Bio-fish extract was added to the main plots at a rate of 5 L/ha and control, sub-plots to three flax varieties (Giza11, L.22 and Sakha4) sub-sub plots, on two cultivation dates of 11 October and 11 November. Agronomic Efficiency (AE) of the flax crop with adding the bio-fish extract for L.22 was 0.034 and 0.018 t grain ha/L for seasons 2016/17 and 2017/18, respectively. The higher grain yield was 1.50 t/ha for season 2016/17 and 0.53 t/ha for season 2017/18, when adding the fish extract for strain L.22 and cultivation date of 11 October. Thus, adding the fish extract led to an increase in grain yield, oil, and fiber content. With the bio-fish fertilization, strain L.22 was better in oil. Also, sowing on November 11 with the addition of fish extract resulted in a higher fiber proportion in the yielded crop.

3D MXene Sponge: Facile Synthesis, Excellent Hydrophobicity, and High Photothermal Efficiency for Waste Oil Collection and Purification

Photothermally assisted superhydrophobic sponges play a vital role in the fields of waste oil collection, oil purification, and solar desalination. However, the widely reported superhydrophobic sponges with photothermal efficiency usually suffer from a post-/premodification process of harmful materials, high loading content of photothermal agents, and low photothermal efficiency. Herein, an MXene-based melamine sponge (MS) was facilely fabricated by hydrogen bonding interaction between the amino groups on the skeleton of the MS and the polar groups on the surface of the as-exfoliated 2D MXene Ti3C2Tx nanosheets. Interestingly, the as-fabricated MXene sponge exhibits excellent hydrophobicity and high photothermal efficiency under an extremely low loading of MXene Ti3C2Tx nanosheets (0.1 wt %). Moreover, the highly hydrophobic sponge also possesses a high oil absorption capacity as high as 176 times of its own weight and keeps stable under multiple absorption/desorption cycling tests. Surprisingly, the surface temperature of the MXene sponge can quickly reach 47 °C under illumination and has good reproducibility during multiple light on/off cycles. The excellent photothermal performance and large oil absorption capacity of the MXene sponge endow the highly hydrophobic sponge with fast solvent evaporation speed and high-purity waste oil collection (99.7 wt % dichloromethane) under illumination, which holds great promise for oil/water separation, leaked oil collection, and photo-driven waste oil collection and purification applications. It is envisioned that this work can open a new strategy for new designs of 3D multifunctional sponges for high-performance waste oil collection and purification.

Impacts of temperature alteration on the drinking water quality stored in plastic bottles

Many people prefer to drink bottled water instead off the tap water. The bottled water is stored in the plastic bottles sometimes for long time. These plastic bottles might leach out some harmful materials into the water especially when exposed to temperature alteration, which may affect human health. This research work focused on investigating the effect of changing temperature on the bottled water quality. The work studied the effect of heating water in plastic bottles by sun, oven, and microwave. The study included also the impact of cooling and freezing the bottled waters. Results showed that temperature alterations caused changes in some physicochemical properties of bottled waters such as decreasing the values of pH and TDS and increasing levels of fluoride and chloride. In addition, the concentration levels of some physiochemical parameters exceeded the permissible values for drinking water. With temperature alterations, all levels of heavy metals in bottled waters were minimal except some small concentrations of copper and zinc. Results confirmed also differences in behavior between the bottled water brands exposed to the same temperature alterations. Heating bottled waters above 50 °C is alarming problem on the water quality. This is because above this degree, many alternations were observed in the water content. The outcomes of this work are useful for improving the current legislation on bottled waters and their storage.

Practical Particulate Matter Sensing and Accurate Calibration System Using Low-Cost Commercial Sensors.

Air pollution is a social problem, because the harmful suspended materials can cause diseases and deaths to humans. Specifically, particulate matters (PM), a form of air pollution, can contribute to cardiovascular morbidity and lung diseases. Nowadays, humans are exposed to PM pollution everywhere because it occurs in both indoor and outdoor environments. To purify or ventilate polluted air, one need to accurately monitor the ambient air quality. Therefore, this study proposed a practical particulate matter sensing and accurate calibration system using low-cost commercial sensors. The proposed system basically uses noisy and inaccurate PM sensors to measure the ambient air pollution. This paper mainly deals with three types of error caused in the light scattering method: short-term noise, part-to-part variation, and temperature and humidity interferences. We propose a simple short-term noise reduction method to correct measurement errors, an auto-fitting calibration for part-to-part repeatability to pinpoint the baseline of the signal that affects the performance of the system, and a temperature and humidity compensation method. This paper also contains the experiment setup and performance evaluation to prove the superiority of the proposed methods. Based on the evaluation of the performance of the proposed system, part-to-part repeatability was less than 2 μg/m3 and the standard deviation was approximately 1.1 μg/m3 in the air. When the proposed approaches are used for other optical sensors, it can result in better performance.

Spatiotemporal Trends, Sources and Ecological Risks of Heavy Metals in the Surface Sediments of Weitou Bay, China

Heavy metals are extremely harmful materials to marine ecosystems and human health. To determine the anthropogenic contributions and ecological risks in Weitou Bay, China, the spatiotemporal variations in the concentrations of heavy metals in surface sediment were investigated during spring 2008 and 2017. The results indicated that high concentrations of pollutants were generally located near the river mouths and along the coast of industrial areas. Principal component analysis indicated that heavy metal contents were mainly affected by industrial waste drainage, urban development, natural weathering and erosion, and interactions between organic matter and sulfides. The potential ecological risk assessment demonstrated that, in 2008, 82% of the sampling sites were at low risk, while 18% were at moderate risk. The situation had deteriorated slightly by 2017, with 73%, 18%, and 9% of stations in Waytou Bay at low, moderate, and very high risk, respectively. Cd was the most harmful metal, followed by Hg. These two elements accounted for more than 80% of the potential ecological risk index (RI) value. The present work analyzed the source of heavy metals, identified the major pollution elements and high risk areas, and provides guidance for pollution control and ecological restoration in Weitou Bay.

Environmental Sustainability through Textile Jewellery for Fashion in Ghana

Jewellery has been widely used for personal beautification or adornment for generations. In recent years, studies have shown the use of alternative materials for jewellery that promotes environmental sustainability. This study conducted by undergraduate students in an art studio context, therefore, aims at producing textile jewellery pieces that are environmentally safe, made from alternative materials including the re-use of waste materials for environmental sustainability. The aesthetico-action research model was employed in a studio-based qualitative research method, in a local cultural context. A field survey revealed that most jewellery is made from potentially harmful materials as compared to beads and textile materials which are environmentally safer. Exploration and adaptation of the concept of reuse with available local materials is recommended for jewellery production to ensure environmental sustainability and avoid environmental risk.

Household kindling behaviours and potential health risks of dioxins exposure in rural Northern China.

The study aimed to analyse the potential risk behind kindling behaviour in Chinese rural families and to provide insights for policymakers in environmental health. A cluster survey was performed on 113 participant's families who were living in the countryside in the north of China, using solid fuels for cooking and heating purpose. A questionnaire survey on their kindling behaviour and family information was administrated. Harmful kindling materials including plastic bottles, plastic planting plates, plastic film mulches, plastic bags, waste foams, and medium density fibreboard (MDF) are targeted in the survey. About one third of participant's families have ever used the listed harmful material for kindling. Based on literature review and the exposure proportion estimated from the questionnaire, we estimated the population attributable fractions (PAF) for all cancer type (10.48-19.48%) and type 2 diabetes (15.57-27.86%) attributable to dioxin exposure. The PAF estimates were greater than our expectation from the view of the global estimate PAF for cancer and T2D. Moreover, we found farming families are more likely to use their farming-related plastic byproducts as kindling material. There is a huge knowledge gap in environmental health in rural China. Although we were not able to measure the specific exposure data, our survey provided a new research aspect for environmental health research and health education. Strengthened environmental health education, better relevant laws, regulations, and supporting policies for regulating rural and farming waste disposal are highly recommended for policymakers in China.

A Thrilling Finding behind Kindling Behavior in Rural Northern China: dioxins exposure and its related risk alert

BACKGROUND AND AIM: During a field research, we discovered a new phenomenon that rural families in northern China were using harmful materials including plastic bottles, bags, and others as kindling material. The aim of this study was to analyze the potential risk behind kindling behavior among Chinese rural families, and to provide insights for policy makers in environmental health. METHODS: A cluster survey was performed on 113 participant’s families using solid fuels for cooking and heating purpose. An electric questionnaire survey on their kindling behavior and family information was administrated. Harmful kindling materials including plastic bottles, plastic planting plates, plastic film mulches, plastic bags, waste foams, and medium density fiberboard (MDF) are targeted in the survey. The population attributable fractions (PAF) for all type cancer and type 2 diabetes (T2D) attributable to dioxins exposure were estimated. A chi square statistics was used for the analysis of driving forces behind these kindling behaviors. RESULTS:About 1/3 participant’s families have ever used the listed harmful material for kindling. Based on literature review and the exposure proportion estimated from the questionnaire, we estimated the PAF for all type cancer (10.48% to 19.48%) and type 2 diabetes (15.57% to 27.86%) attributable to dioxins exposure. The PAF estimates were greater than our expectation from view of the global estimate PAF for cancer and T2D. Availability, age, ignition frequency and favorite kindling material are significantly different among different behavior groups (p0.05). Moreover, we found farming families are more likely to use their farming related plastic byproducts as kindling material. CONCLUSIONS:There is a huge knowledge gap among environmental health in rural China. Our survey provided a new research aspect for environmental health research and health education. Strengthened environmental health education, better relevant laws, regulations, and supporting policies for regulate rural and farming waste disposal are highly recommended for policy makers in China. KEYWORDS: Dioxins exposure, Solid fuels, Indoor air quality, Kindling materials, Public health, Behaviors

Microscopic pyrolysis mechanism on the octyphenylsiloxane flame retarded polycarbonate by reactive molecular dynamics

Pyrolysis mechanisms and flame retardant properties of polycarbonate (PC) and PC/ octyphenylsiloxane (OPS) composites at different temperatures (2000–4000 K with an interval of 500 K) were studied using reactive force field (ReaxFF) molecular dynamics simulation. The initial decomposition mechanism, products distribution, and main products generation and consumption paths of PC and PC/OPS composites were analyzed. Results showed that decomposition of PC molecular chain was caused by the rupture of the CO bond, and the decomposition of OPS molecule was caused by the rupture of the C-Si bond. The breaking of partial CSi bond made OPS from cage structure into a lamellar-like or reticular structure, which has been proven this structure was a key factor to improve the flame retardance of PC by suppressing the transfer of heat, flammable volatile gaseous products. From the potential energy and decomposition time of PC and PC/OPS composites, the addition of OPS slowed down the decomposition rate of the PC molecular chain and improved the thermal stability of the composites. These have overall good agreement with the reported results. The amounts of CO2, CO, C6H5OH and their derivatives in PC/OPS composites were lower than those in PC at the later stage of reaction, which was because unsaturated Si atoms in OPS adsorbed small oxygen-containing molecules to suppress these harmful materials. Moreover, OPS promoted the combination of molecular products into carbon clusters and large thermally stable organic structures. Thus, the ReaxFF method could be effectively used to study the pyrolysis mechanism of PC/OPS composites, and provide a new method for the prediction and analysis of flame retardance.

Use of treated cement kiln dust as a nano material partially replaced in cement mortars

Cement kiln dust (CKD) is a by-product material of cement manufacturing. The composition of this material is approximately like the cement composition but it carries high ratio of alkali which is harmful material if it is used in structural construction members. In this study it was used after removing most of alkali by washing, in cement mortars as partial replacement of cement. After washing it was left to be dried. The material was grinded by Los Angeles machine firstly and then milled by a planetary mill in periods of 1,1.5,2,2.5,3,3.5, and 4 hours respectively to reach nano sizes of particles. It was added to cement mortars using five ratios, 0% (without milling as control ratio) and an addition of 5%, 10%, 15%, and 20% ratios compared to cement weight respectively. The properties which were studied include compressive strength of mortar through curing periods 7, 28, 56 days, physical and chemical properties of the mortars. The results of this work ensure the work of one of the authors in the literature and an improvement in mortar compressive strength reaches 35%. Other physical and chemical properties were also improved. Depending upon the governed results washed CKD can be used safely in cement mortars.

Effect of Polymer SBR on Strength Reduction in Concrete Immersed in Drainage and Ground Water

Concrete structures suffer from the impact of many harmful attacking materials that affect theproperties of the main material in them, which is concrete. These structures are also, exposedto the negative impact of many hostile environments such as soils containing harmful salts andharmful acids. A number of precautions should be considered in order to protect the concreteused in such structures. Adding polymer to concrete components as a percentages weight ofcement is one of the methods for producing polymer-modified concrete, which has lowpermeability, better mechanical properties and is more resistant to the negative effects ofharmful environmental factors. The utilization of polymers could help in protecting structuresand enhancing concrete strength. In this study, concrete mixes were prepared with inclusion ofstyrene butadiene rubber (SBR) polymer at four percentages (0%, 5%, 7% and 10% by cementweight). Co-polymers of butidine with styrene (styrene-butadine rubber (SBR)), are a group oflarge-volume synthetic rubbers. High adhesion occurs between the polymer films that formand cement hydrates. This action gives improves the properties of concrete such as flexuraland compressive strength and gives also a higher durability. The investigation was extended toevaluate the compressive strength of the SBR concrete mixes immersed in three types ofwaters: tap, drainage and ground water, at three different ages. The results showed that SBRpolymer enhanced the compressive strength of concrete significantly. A comparison betweenreduction in strength of concretes immersed in these three types of waters was also presented.Moreover, the presence of SBR polymer led to reduced loss in strength of concrete specimensimmersed in drainage and ground water. A proposed model to determine the compressivestrength of concrete specimens immersed in drainage and ground waters was deduced. Thismodel could be a helpful tool for rapid and easy estimation of the strength of concretespecimens immersed in drainage and ground water at different contents of SBR polymer. Theresults showed the highest improve in compressive strength to be associated with 7% SBRmixes at the three tested ages. The increases in this strength at days 7, 28 and 56 with inclusionof 7% SBR polymer were 112.8%, 113.9% and 116%, respectively, compared to OPC mix.

Tribological Studies of Bamboo Fibre Reinforced Epoxy Composites Using a BOD Technique.

To reduce the emission of harmful materials into the ecosystem, researchers have been exploring the potential of manufacturing polymeric composites based on natural fibres. Although the large area of application of these materials has encouraged investigations of their performance under various loading conditions, less research has been conducted on their tribological behaviour. Hence, in this study, tribological tests were conducted on epoxy composites based on bamboo fibres. The wear performance of bamboo fibre reinforced epoxy was tested using various operating parameters, and the worn surfaces were examined using optical microscopy. The results revealed that the specific wear rate of the composites reduced since the epoxy was reinforced with bamboo fibres. Scanning electron microscopy analysis showed different wear mechanisms and damages.

A study on nanomaterials for water purification

Many scientific and technological areas have been affected by nanotechnology, including environmental safety. Environmental uses of nanotechnology include the remediation of water and wastewater treatment to remove pollutants, pathogens, and other harmful materials. Diverse shapes, varied composites, and functionalized with active components are only a few of the multitude of ways nanomaterials have been created. Nanotechnology provided a viable solution to ensuring an abundant supply of water. Nanomaterials have emerged as a hot topic in environmental research because of their highly specialized surface areas, microinterface characteristics, and remediation potential. The review paper will include a range of nanomaterials, such as graphene nanomaterials (GNMs), TiO2 nanoparticles (NPs), nanoscale zero-valent iron (nZVI), Fe3O4 NPs, ZnO NPs, silver nanoparticles (Ag NPs), carbon nanotubes (CNTs), and some additional nanomaterials as well as various nanocomposite materials. More importantly, in the future, Nanomaterial's potential use in the treatment of water and wastewater is also discussed.