Termeh Teymoorian

Bio: Termeh Teymoorian is an academic researcher from Amirkabir University of Technology. The author has contributed to research in topics: Freundlich equation & Adsorption. The author has an hindex of 3, co-authored 4 publications receiving 15 citations.

Direct and Indirect Effects of SARS-CoV-2 on Wastewater Treatment

Abstract: The novel SARS-CoV-2 is expanding internationally. While the current focus is on limiting its transmission from direct contact with infected patients and surfaces during the pandemic, the secondary transmission potential via sewage should not be underestimated, especially in low-income and developing countries with weak wastewater treatment technologies. Recent studies have indicated SARS-CoV-2 positivity also be detected in the feces of patients. Therefore, the risk of transmission and infection can be increased into sewage by the fecal-oral way, mainly in some parts of the globe with a high amount of open defecation. This review collected scattered data and recent studies about the direct and indirect effects of coronavirus in the water cycle. The direct impacts of COVID-19 on wastewater are related to the presence of the coronavirus and suitable viral removal methods in different phases of treatment in wastewater treatment plants. The indirect effects of COVID-19 on wastewater are related to the overuse of cleaning and disinfecting products to protect against viral infection and the overuse of certain drugs to protect against virus or novel mental problems and panic to COVID-19 and consequently their presence in wastewater. This unexpected situation leads to changes in the quality of wastewater and brings adverse and harmful effects for the human, aquatic organisms, and the environment. Therefore, applying effective wastewater treatment technologies with low toxic by-products in wastewater treatment plants will be helpful to prevent the increasing occurrence of these extra contaminants in the environment.

Challenges, Strategies, and Recommendations for the Huge Surge in Plastic and Medical Waste during the Global COVID-19 Pandemic with Circular Economy Approach

Abstract: After December 2019, the globe was affected by a new coronavirus (SARS-CoV-2) that causes severe respiratory illnesses, which is responsible for increasing environmental problem consequences related to the extra consumption of medical waste and single-use plastics (such as personal protective equipment (PPE) and packaging plastics). Although the consumption of these plastics protects our life during this crisis, it is pivotal to move toward plastic recycling processes and environmentally friendly and sustainable alternatives, like bio-based degradable plastics with a circular economy perspective. This review article collected scattered information and provided a future perspective on how worldwide COVID-19 disruption can perform as a catalyst to improve plastic and medical waste management. Additionally, this paper illustrates the most effective disinfection technologies for COVID-19 wastes, such as high/low heat technologies and chemical disinfection, and PPE reusing processes, including dry heat, vaporized hydrogen peroxide, ozone, and UV light during the outbreak. In this vein, medical waste treatment facilities must be more automatic, with a minimum of personnel involved. Moreover, some recent valid guidelines from different international organizations and countries, future outlook, and practical recommendations that could be effective during this epidemic or even in the post-pandemic world for plastic and medical waste management were provided. Ultimately, governments should improve their waste management because of the potential of pathogen transmission or increased plastic and medical waste generation and try to enhance the environmental knowledge of society. People also should revise their viewpoints on plastic consumption by elevating sustainable behaviors, abandoning old habits, and adjusting to novel ones.

N, S doped carbon quantum dots inside mesoporous silica for effective adsorption of methylene blue dye

Abstract: This study aimed to develop non-metal elements for doping carbon quantum dots (CQDs) with nitrogen and sulfur (N, S-CQDs), which loaded inside hexagonal mesoporous silica (HMS) in order to effectively remove methylene blue dye (MB) from an aqueous solution. The histidine and cysteine amino acids were used as the source for synthesis N, S-CQDs through the hydrothermal method. Morphology and structure of the N, S-CQDs, and adsorbent (N, S-CQDs/HMS) were characterized by using different microscopic and spectroscopic techniques. The adsorption parameters such as adsorbent dosage (0.25–1 g/L), pH (2–10), contact time (15–75 min), and initial MB dye concentration (20–300 mg/L) were investigated. The maximum adsorption capacity and removal efficiency of MB were determined at 370.4 mg/g and 97%, respectively, under optimum conditions at 303 K. The adsorption isotherm studies were fitted with the Freundlich isotherm equation, and the dye removal kinetics of the adsorbent followed the pseudo-second-order model. Thermodynamic studies showed that the adsorption process had exothermic and spontaneous behavior. The removal of MB next to the Rhodamine B and Reactive Black 5 dyes indicated that the N, S-CQDs/HMS had excellent selective behavior for MB absorption. This prepared adsorbent could be well recycled with suitable activity after four repeated adsorption–desorption cycles. Results revealed that the porous characters, surface area, charge properties, reduction in the bandgap, and quantum yield of the N, S-CQDs/HMS were essential factors that affected dye adsorption.

A review of emerging PFAS contaminants: sources, fate, health risks, and a comprehensive assortment of recent sorbents for PFAS treatment by evaluating their mechanism

Abstract: Per- and polyfluoroalkyl substances (PFASs) have highly complex behavior in the environment and are environmentally persistent. Exposure to PFASs causes cancer, liver toxicity, effect on the thyroid hormones, and also brings risks for the animal’s health. PFASs are separated into two categories: non-polymers and polymers, and most parts of the study of PFASs focus on non-polymers because they are more found in the environments. Urban water cycles such as drinking water, surface water, groundwater, and wastewater have been faced with the occurrence of PFASs, and PFOS and PFOA are the most detected PFASs. Various methods have been applied to remove PFASs which are divided into two main categories: separation and destruction. The PFASs destruction is still challenging in practice because of the powerful C–F bond and has only been utilized at the laboratory and small scale. Therefore, sorption is an eco-friendly and cost-effective technique with high efficacy that is commonly applied to eliminate PFASs from wastewater. In this review, most important sorption techniques used to remove long- and short-chain PFASs are collected such as powdered or granular activated carbons, carbon nanotubes, biochar, polysaccharide-based adsorbents, ion exchange resins, and minerals. Additionally, the possible mechanisms of PFASs sorption on various adsorbents are summarized, and different interactions such as electrostatic and hydrophobic interactions are reviewed. However, coexisting of inorganic anions and cations, natural organic matters, and other organic contaminants that generally exist in wastewater can affect the sorption of PFASs. Moreover, environmentally friendly and economical ways for the regeneration of adsorbents were summarized. Although this process needs more research and evaluation.

Tracking PFAS in Drinking Water: A Review of Analytical Methods and Worldwide Occurrence Trends in Tap Water and Bottled Water

Abstract: Per- and polyfluoroalkyl substances (PFAS) used in various industrial applications are pollutants of concern for the environment and human health. Drinking water consumption is one key exposure pathway to PFAS, as recently highlighted by multiple studies on their occurrence in tap and bottled water worldwide. However, PFAS quantification at low part-per-trillion (ng/L) or part-per-quadrillion (pg/L) concentrations remains challenging. PFAS presence in blanks and incomplete method recoveries can lead to false positives or negatives; PFAS concentration changes under different storage durations or conditions can also affect accuracy and precision. Here, we review the most recent data related to analytical methods that were used in research articles for the detection and quantification of PFAS from drinking water. Commonly encountered pitfalls are summarized, and analytical performance is appraised including detection limits, recovery, matrix effects, and other quality assurance/quality control endpoints. In addition, we collated available guidelines for health advisory levels of PFAS in tap water. Finally, we compiled concentration data on legacy and emerging PFAS in tap and bottled water.

An empirical literature analysis of adsorbent performance for methylene blue uptake from aqueous media

Abstract: Methylene blue (MB) is a heterocyclic aromatic compound used as a medication or as a synthetic dye for textiles. Due to its ecotoxicity, researchers have been investigating its mitigation by the adsorption process. The aim of this review was to analyse the performance of different classes of adsorbent for MB dye uptake based on their maximum adsorption capacity. MB was chosen for this analysis due to the large volume of work that has been done on it over the years. Over 500 research papers published on MB adsorption (within the past 5 years were analysed). This was to help guide the research area on the best class adsorbents for MB uptake thereby pointing the areas of biggest potential to investigators. Composites adsorbents (31%) were the most frequently studied for MB uptake. Other popularly used types were biosorbents (16%) and activated carbon (16%). Polymers and resins, and organic and inorganic nanoparticles were the more favoured constituents for composite adsorbent development. For similar data indices, composite adsorbents yielded a higher adsorption capacity. This suggests that composite adsorbents (especially with constituents of polymers, resins and nanoparticles) perform better for MB uptake. Though polymers and resins had the highest mean, the highest median was for activated carbon. Composite adsorbent was the second highest for mean, median and number of adsorbents above the 1000 mg/g threshold. It was surmised from the analysis that polymers, resins and composites are the best classes of adsorbents for MB uptake.

Direct and Indirect Effects of SARS-CoV-2 on Wastewater Treatment

Abstract: The novel SARS-CoV-2 is expanding internationally. While the current focus is on limiting its transmission from direct contact with infected patients and surfaces during the pandemic, the secondary transmission potential via sewage should not be underestimated, especially in low-income and developing countries with weak wastewater treatment technologies. Recent studies have indicated SARS-CoV-2 positivity also be detected in the feces of patients. Therefore, the risk of transmission and infection can be increased into sewage by the fecal-oral way, mainly in some parts of the globe with a high amount of open defecation. This review collected scattered data and recent studies about the direct and indirect effects of coronavirus in the water cycle. The direct impacts of COVID-19 on wastewater are related to the presence of the coronavirus and suitable viral removal methods in different phases of treatment in wastewater treatment plants. The indirect effects of COVID-19 on wastewater are related to the overuse of cleaning and disinfecting products to protect against viral infection and the overuse of certain drugs to protect against virus or novel mental problems and panic to COVID-19 and consequently their presence in wastewater. This unexpected situation leads to changes in the quality of wastewater and brings adverse and harmful effects for the human, aquatic organisms, and the environment. Therefore, applying effective wastewater treatment technologies with low toxic by-products in wastewater treatment plants will be helpful to prevent the increasing occurrence of these extra contaminants in the environment.