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Abstract Although, different plant species were utilized for the fabrication of polymorphic, hexagonal, spherical, and nanoflower ZnO NPs with various diameters, few studies succeeded in synthesizing small diameter ZnO nanorods from plant extract at ambient temperature. This work sought to pioneer the ZnO NPs fabrication from the aqueous extract of a Mediterranean salt marsh plant species Limoniastrum monopetalum (L.) Boiss. and assess the role of temperature in the fabrication process. Various techniques have been used to evaluate the quality and physicochemical characteristics of ZnO NPs. Ultraviolet–visible spectroscopy (UV–VIS) was used as the primary test for formation confirmation. TEM analysis confirmed the formation of two different shapes of ZnO NPs, nano-rods and near hexagonal NPs at varying reaction temperatures. The nano-rods were about 25.3 and 297.9 nm in diameter and in length, respectively while hexagonal NPs were about 29.3 nm. The UV–VIS absorption spectra of the two forms of ZnO NPs produced were 370 and 365 nm for nano-rods and hexagonal NPs, respectively. FT-IR analysis showed Zn–O stretching at 642 cm−1 and XRD confirmed the crystalline structure of the produced ZnO NPs. Thermogravimetric analysis; TGA was also used to confirm the thermal stability of ZnO NPs. The anti-tumor activities of the two prepared ZnO NPs forms were investigated by the MTT assay, which revealed an effective dose-dependent cytotoxic effect on A-431 cell lines. Both forms displayed considerable antioxidant potential, particularly the rod-shaped ZnO NPs, with an IC50 of 148.43 µg mL−1. The rod-shaped ZnO NPs were superior candidates for destroying skin cancer, with IC50 of 93.88 ± 1 µg mL−1 ZnO NPs. Thus, rod-shaped ZnO NPs are promising, highly biocompatible candidate for biological and biomedical applications. Furthermore, both shapes of phyto-synthesized NPs demonstrated effective antimicrobial activity against various pathogens. The outcomes highlight the potential of phyto-synthesized ZnO NPs as an eco-friendly alternative for water and wastewater disinfection.

Abstract Chitosan–walnut shells (Ch–W) composite was tested for the removal of levofloxacin from water. Various experimental factors were examined at different contact time intervals. The prepared composite exhibited maximum uptake capacity of 7.43 mg g−1 for levofloxacin with 0.5 g L−1 Ch–W dose at 45 min and pH = 7. Linear and nonlinear isotherm/kinetic models have been investigated, and the pertinency of the models was confirmed by correlation coefficients (R 2) and error functions. Consequently, the adsorption of levofloxacin could be more accurately described by the nonlinear pseudo-second-order and Langmuir as well as Temkin models (R 2 ˃ 0.98). Optimization modeling of levofloxacin was performed using a central composite design. The independent parameters; initial concentration, pH, and Ch–W dose, were selected while levofloxacin removal was the response. The maximum levofloxacin removal was 75.7% and 94.2% at concentrations of 4 mg L−1 and 2 mg L−1, respectively. Furthermore, 3D surface plots with the interaction effects of the investigated factors are presented. The developed model was reliable for further study and prediction owing to the closeness between the experimental and predicted values. The individual and interacting factors were found to be significant except for “concentration x dose” based on the ANOVA. The models confirmed the experimental results with R 2, R 2 adjusted, and R 2 predicted values ˃ 0.939. The continuity adsorption cycles were tested for reuse and revealed that the removal of levofloxacin was decreased ~ 23% after six cycles. Hence, the prepared composite has the potential to remove antibiotics from water.

Abstract In the present study, a green, sustainable, simple and low-cost method was adopted for the synthesis of ZnO NPs, for the first time, using the aqueous extract of sea lavender, Limonium pruinosum (L.) Chaz., as a reducing, capping, and stabilizing agent. The obtained ZnO NPs were characterized using ultraviolet–visible spectroscopy (UV–VIS), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The UV–Vis spectra of the green synthesized ZnO NPs showed a strong absorption peak at about 370 nm. Both electron microscopy and XRD confirmed the hexagonal/cubic crystalline structure of ZnO NPs with an average size ~ 41 nm. It is worth noting that the cytotoxic effect of the ZnO NPs on the investigated cancer cells is dose-dependent. The IC50 of skin cancer was obtained at 409.7 µg/ml ZnO NPs. Also, the phyto-synthesized nanoparticles exhibited potent antibacterial and antifungal activity particularly against Gram negative bacteria Escherichia coli (ATCC 8739) and the pathogenic fungus Candida albicans (ATCC 10221). Furthermore, they showed considerable antioxidant potential. Thus, making them a promising biocompatible candidate for pharmacological and therapeutic applications.

Abstract In this work, the synthesis of an rGO/nZVI composite was achieved for the first time using a simple and green procedure via Atriplex halimus leaves extract as a reducing and stabilizing agent to uphold the green chemistry principles such as less hazardous chemical synthesis. Several tools have been used to confirm the successful synthesis of the composite such as SEM, EDX, XPS, XRD, FTIR, and zeta potential which indicated the successful fabrication of the composite. The novel composite was compared with pristine nZVI for the removal aptitude of a doxycycline antibiotic with different initial concentrations to study the synergistic effect between rGO and nZVI. The adsorptive removal of bare nZVI was 90% using the removal conditions of 25 mg L−1, 25 °C, and 0.05 g, whereas the adsorptive removal of doxycycline by the rGO/nZVI composite reached 94.6% confirming the synergistic effect between nZVI and rGO. The adsorption process followed the pseudo-second order and was well-fitted to Freundlich models with a maximum adsorption capacity of 31.61 mg g−1 at 25 °C and pH 7. A plausible mechanism for the removal of DC was suggested. Besides, the reusability of the rGO/nZVI composite was confirmed by having an efficacy of 60% after six successive cycles of regeneration.

Global demand for freshwater is rapidly escalating. It is highly essential to keep pace with the necessities of the increasing population. The effluents of wastewater are gradually identified as a reservoir of resources for energy generation and economic boom. Henceforth, most wastewater and sludge have great potential for reuse and recycling. The re-utilization and valorization of wastewater and sludge contribute to accomplishing sustainable development goals, combating water scarcity, and alleviating adverse environmental impacts of wastewater on the environmental components. The present article highlights the most novel approaches for wastewater treatment for the waste valorization of different industrial origins and the generation of value-added products and recovery of biopolymers, vitamins, enzymes, dyes, pigments, and phenolic compounds. We highlighted the life cycle assessment and techno-economic analysis. In addition, we have addressed a critical overview of the barriers to the large-scale application of resource recovery strategies and economic, environmental, and social concerns associated with using waste-derived products.

Introduction: One of the most important steps in risk assessment is the selection of assessment methods. Traditionally, when developing measures to reduce the level of occupational morbidity and industrial injuries, the results of an analysis of the causes, types of events and other factors that led to accidents are used. But such an approach does not meet modern requirements. For an adequate assessment of occupational risks, it is necessary to have objective data from different time periods: the onset of traumatic events in the past, the current state of threats to life and health of people, and the future state of threats in industrial sectors. Methods: Mathematical modeling remains the main means of scientific support for occupational risk management. The Elmeri system was chosen for occupational risk assessment in this study, which can be easily and quickly used in any industry and in enterprises of all sizes. A critical analysis of various approaches to managing occupational risks in enterprises was applied to identify the strengths and weaknesses of these approaches. The method of generalizing the most effective approaches to occupational risk management was applied to develop the algorithm of occupational risk management decisions in industrial sectors in case of uncertainty. Results: An occupational risk management algorithm has been developed to substantiate management decisions on planning measures to reduce risk, the implementation of which ensures the effectiveness of measures aimed at reducing risk. Research has shown that if the decision-making situation is characterized by conditions of uncertainty (it is impossible to obtain mathematical models of acceptable accuracy), the assessment of the predictive values of occupational risk is carried out exclusively by an expert. Thus, the occupational risk indicator used at the final stage of planning activities determines the degree of achievement of the result of solving the task. Conclusion: It has been established that in conditions of uncertainty (lack of necessary data or available data are incomplete or unreliable), experts involved in solving the problem of risk management use their own knowledge and experience in solving similar problems. As a promising direction for further research, it should be noted the development of a methodology for a comprehensive assessment of the effectiveness of operational management decisions for planning and implementing measures to reduce risks

Abstract A facile approach to synthesize reduced graphene oxide (rGO) was investigated using three different extract concentrations of Tecoma stans leaves as reducing/capping agents. The surface morphology of the rGOs was examined by scanning electron microscopy with energy dispersive X-ray. The optimum prepared rGOs were confirmed with characteristic peaks at ~ 280 nm using UV–Vis Spectroscopy. Fourier-transform infrared spectroscopy results indicated the capacity of plant extracts to reduce the oxygen functional groups on graphite oxides’ surfaces. Furthermore, the organic constituents of the plant extract were determined to highlight the reduction mechanism of graphene oxide to rGO. The optimized rGO was subsequently utilized as an adsorbent for the removal of Ni (II) from simulated wastewater. Adsorption experiments were conducted using methods of one factor at a time as well as Box Behnken Design. The Ni (II) adsorption is fitted well to the non-linear isotherm models and the calculated maximum uptake capacity was 69 mg g− 1. The optimum removal of Ni (II) was found 93% with pH of 6, initial Ni (II) concentration of 2 mg L− 1, and rGO dose of 0.2 g L− 1. The reliability of the developed model was 99.4% between experimental and predicted values. In addition, the average desorption efficiency of Ni (II) was 94%, which highlight the applicability of rGO reusability.

Aquatic macrophytes biomasses provide an opportunity of using their unwanted biomasses that cause ecological disturbance as green corrosion inhibitors. The extracts of water hyacinth (Eichhornia crassipes) and common reed (Phragmits australis) were prepared and assessed, for mild steel corrosion inhibition. The inhibitive effect has been investigated by electrochemical impedance spectroscopy and potentiodynamic polarization techniques. Increasing aquatic and ethanolic extract concentration of both plant extracts increased the inhibition efficiency (% IE). The maximum IE was recorded 86.8 and 89.6% for ethanolic extracts of water hyacinth and common reed. The corrosion current density (icorr) was recorded as 0.534 and 0.369 mA cm−2 for water hyacinth and common reed, respectively, at the maximum concentration. Theoretical fitting of isotherms, Langmuir, Florry–Huggins, and kinetic–thermodynamic models were analyzed to clarify the nature of adsorption behaviour. The % IE of plants extract for mild steel corrosion was evaluated and optimized by 2(3) full factorial experimental design. Three factors have been studied namely: extraction method, pH and extract dose. The optimum conditions were at low pH and high plant extract dose concentration especially with ethanolic extraction. The validation models were calculated with R2 ≥ 0.986. The effectiveness of the investigated green inhibitors was also verified using the response surface methodology (RSM).

Water shortages are one of the problems caused by global industrialization, with most wastewater discharged without proper treatment, leading to contamination and limited clean water supply. Therefore, it is important to identify alternative water sources because many concerns are directed toward sustainable water treatment processes. Nanofiltration membrane technology is a membrane integrated with nanoscale particle size and is a superior technique for heavy metal removal in the treatment of polluted water. The fabrication of nanofiltration membranes involves phase inversion and interfacial polymerization. This review provides a comprehensive outline of how nanoparticles can effectively enhance the fabrication, separation potential, and efficiency of NF membranes. Nanoparticles take the form of nanofillers, nanoembedded membranes, and nanocomposites to give multiple approaches to the enhancement of the NF membrane’s performance. This could significantly improve selectivity, fouling resistance, water flux, porosity, roughness, and rejection. Nanofillers can form nanoembedded membranes and thin films through various processes such as in situ polymerization, layer-by-layer assembly, blending, coating, and embedding. We discussed the operational conditions, such as pH, temperature, concentration of the feed solution, and pressure. The mitigation strategies for fouling resistance are also highlighted. Recent developments in commercial nanofiltration membranes have also been highlighted.

Abstract Environmentally friendly copper oxide nanoparticles (CuO NPs) were prepared with a green synthesis route without using hazardous chemicals. Hence, the extracts of mint leaves and orange peels were utilized as reducing agents to synthesize CuO NPs-1 and CuO NPs-2, respectively. The synthesized CuO NPs nanoparticles were characterized using scanning electron microscopy (SEM), Energy Dispersive X-ray Analysis (EDX), BET surface area, Ultraviolet–Visible spectroscopy (UV–Vis), and Fourier Transform Infrared Spectroscopy (FT-IR). Various parameters of batch experiments were considered for the removal of Pb(II), Ni(II), and Cd(II) using the CuO NPs such as nanosorbent dose, contact time, pH, and initial metal concentration. The maximum uptake capacity (qm) of both CuO NPs-1 and CuO NPs-2 followed the order of Pb(II) > Ni(II) > Cd(II). The optimum qm of CuO NPs were 88.80, 54.90, and 15.60 mg g−1 for Pb(II), Ni(II), and Cd(II), respectively and occurred at sorbent dose of 0.33 g L−1 and pH of 6. Furthermore, isotherm and kinetic models were applied to fit the experimental data. Freundlich models (R2 > 0.97) and pseudo-second-order model (R2 > 0.96) were fitted well to the experimental data and the equilibrium of metal adsorption occurred within 60 min.

This research was undertaken to optimize the Se(IV) adsorption from aqueous solutions by Cyperus laevigatus biomass and green-synthesized nanosilver (AgNPs). A full 24 factorial experimental design was utilized to distinguish the effects of pH, initial metal concentration (Co), adsorbent dose concentration (C. laevigatus biomass, X1 & AgNPs, X2) and contact time (t). Response surface methodology (RSM) was also applied to assess the factors interactions. The influence of selected variables on Se(IV) uptake capacity was studied and a factorial model was designed to detect the variables’ effects and their interactions. The range of pH was 2–8, Co was 100–400 mg L−1, X1 was 1–5 g L−1, X2 was 0.025–0.1 g L−1 and t was 1–8 h. The significant effects for Se(IV) adsorption on C. laevigatus biomass were ascribed to pH, Co, pH.X, and pH.Co.X, while in case of AgNPs, Co and X2 were detected. Normal distribution was noted between the model values (predicted) and the observed (experimental). RSM design revealed the same results obtained from factorial design. The characterization of both sorbents by TEM revealed that the granulated texture of AgNPs possesses high porosity and clear surface that precedes the high sorption capacity of Se(IV).

Scientific advancements from 2002 to 2020 for coronaviruses, i.e., SARS-CoV and MERS-CoV outbreaks, could lead towards a better understanding of the exposure to a health crisis. However, data on its transmission routes and persistence in the environment is still in need of the hour. In this review, we discuss the impact of environmental matrices on dealing with the consequences of the global COVID-19 outbreak. We have compiled the most recent data on the epidemiology and pathogenesis of the diseases. The review aims to help researchers and the larger public recognize and deal with the consequences of co-occurring viral indicators for COVID-19 and provide nano-technological perspectives of possible diagnostic and treatment tools for further studies. The review highlights environmental wastes such as hospital wastewater effluents, pathogen-laden waste, pathogen-laden ground/surface water, wastewater sludge residues and discusses their potential remediation technologies, i.e., pathogen-contaminated soil disposal, municipal and medical solid waste collection, recycling, and final disposal. Finally, holistic suggestions to tackle environmental-related issues by the scientific community have been provided, where scientists, consultants may involve in a tiered assessment from the hazard to risk management in the post-COVID-19 world.

Fluoride ions present in drinking water are beneficial to human health when at proper concentration levels (0.5–1.5 mg L−1), but an excess intake of fluoride (>1.5 mg L−1) may pose several health problems. In this context, reducing high fluoride concentrations in water is a major worldwide challenge. The World Health Organization has recommended setting a permissible limit of 1.5 mg L−1. The application of electrocoagulation (EC) processes has received widespread and increasing attention as a promising treatment technology and a competitive treatment for fluoride control. EC technology has been favourably applied due to its economic effectiveness, environmental versatility, amenability of automation, and low sludge production. This review provides more detailed information on fluoride removal from water by the EC process, including operating parameters, removal mechanisms, energy consumption, and operating costs. Additionally, it also focuses attention on future trends related to improve defluoridation efficiency.

Background: Prematurity and congenital abnormalities happened as a result of umbilical cord entanglement. It is possible to link cord-related problems, in which the foetal circulation is hampered by obstruction of the umbilical veins, to a major fraction of instances of intrauterine foetal death. Objectives: To evaluate how the results of the delivery are affected by nuchal umbilical cord (UC) loops during labour. Patients and Methods: A cross-sectional study included 470 women with singleton deliveries between 37-41 weeks of gestation from May 2019 till November 2020. Nuchal cord presence was categorized as either present or missing. The quantity of loops and the delivery results were noted, if applicable. After birth, the length of the umbilical cord was measured to see if nuchal cord loops were present. Results: The participants were classified into cases group (those with nuchal cord, n-220) and control group (without nuchal cord, n=250). The length of UC was significantly higher in the cases group (89.30 ± 14.44 vs. 73.57 ± 18.66 cm, P<0.0001) No significant differences between both groups regarding the rate of Apgar scores 7 (P-0.21), neonatal care unit admission (P-0.96) and perinatal mortality (P-0.26). Meanwhile, the length of UC was significantly higher in those with multiple nuchal loops (n=36) than single nuchal loop (n=184) (100.35 ± 1042 vs. 86,84 ± 14.07 cm. P<0.0001). The rate of Apgar scores 7, neonatal care unit admission and perinatal mortality was significantly higher in women with multiple nuchal loops than with single nuchal loop (P-0.007, 0.011, 0.043, respectively). Conclusions: Multiple nuchal cord loops increase the risk of prenatal morbidity and death in newborns. Nuchal cord loops are more frequent when the UC is long. [ABSTRACT FROM AUTHOR]