Ain Témouchent University

Benhadria N., Hachemaoui M., Zaoui F., Mokhtar A., Boukreris S., Attar T., Belarbi L., Boukoussa B.

In this paper, the precipitation method was used to synthesize CuO nanoparticles (NPs). Sodium dodecyl sulfate (SDS) and Cetyltrimethylammonium Bromide (CTAB) were used as a surfactant to modify the surface morphology of the CuO NPs. To investigate the characteristics of the CuO NPs, X-ray diffraction technique (XRD), X-Ray photoelectron spectrometry (XPS), Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and Energy dispersive X-ray analysis (EDAX) were used. The catalytic activities of as prepared CuO NPs were evaluated by monitoring reduction of MB dye in the presence of NaBH4 as reducing agent. Effect of catalyst mass, concentration of NaBH4 and concentration of MB dye were investigated. The best results for the reduction of MB dye were obtained by the CuO–SDS catalyst. The results showed that 10 min of reaction time was sufficient to have the total degradation of MB dye. The reuse of the CuO–SDS catalyst for five cycles has shown interesting results via the reduction of MB dye without losing its effectiveness.

Bentout S., Tridane A., Djilali S., Touaoula T.M.

As the COVID-19 is still spreading in more than 180 countries, according to WHO. There is a need to understand the dynamics of this infection and predict its the impact on the public health capacity. This work aims to forecast the progress of the disease in three countries from different continents: The United States of America, the United Arab Emirates and Algeria. The existing data shows that the fatality of the disease is high in elderly people and people with comorbidity. Therefore, we consider an age-structured model. Our model also takes into consider two main components of the COVID-19 (a) the number of Infected hospitalized people, therefore, we estimate the number of beds (acute and critical) needed (2) the possible infection of the healthcare personals (HCP). Hence, the model predict the peak time and the number of infectious cases at the peak before and after the implementation of non-pharmaceutical interventions (NPI), and we also compare this finding with case of full lockdown. Finally, we investigate the impact of the shortage of proper personal protective equipment (PPE) on the spread of the disease.

Rachid H.B., Noureddine D., Benali B., Adin M.Ş.

Mekki A., Mokhtar A., Hachemaoui M., Beldjilali M., Meliani M.F., Zahmani H.H., Hacini S., Boukoussa B.

Three zeolites with different structures (mazzit, faujasite and MFI) were prepared by hydrothermal way, and then were used to stabilize the Fe and Ni nanoparticles using ion exchange followed by treatment with a solution of NaBH 4 as reducing agent. The designed nanocatalysts were used in the catalytic reduction of methylene blue dye (MB) and 4-nitrophenol (4-NP) in a simple and binary system under NaBH 4 solution to determine their effectiveness in wastewater treatment. The obtained samples were characterized by XRD, XPS, nitrogen sorption at 77 K, XRF, FTIR, UV–vis, SEM and TEM. The obtained results revealed that the structure of the zeolites was well retained after immobilization of metal nanoparticles (NPs), but their textural properties were slightly reduced. The XPS results clearly show that the zero charge nanoparticles were well obtained using NaBH 4 solution. As confirmed by TEM the nanoparticles were well dispersed in the surface of the zeolites their sizes were around 3–13 nm for the zeolites modified by Fe NPs and 2–6 nm for those modified by Ni NPs. The catalyst Ni–Y exhibited excellent catalytic activity towards the reduction of MB dye and 4-NP in binary and simple system due to its large surface area containing well dispersed Ni nanoparticles. The rate constant in a simple system was 0.02 s −1 and 0.005 s −1 for 4-NP and MB dye respectively, while in the binary system was 0.002 s −1 and 0.014 s −1 . The catalyst Ni–Y was used in five consecutive experiments without important loss of activity, confirming its stability. • Stabilization of Ni and Fe NPs on MFI, Faujasite and mazzit zeolites. • Comparative study towards the catalytic reduction of 4-NP and MB in a simple and binary system. • Excellent performance catalytic hydrogenation towards both pollutants obtained by the modified zeolite Y. • The catalyst Ni–Y can be re-used for five cycles without loss of its efficiency.

Tiwari S., Si Mohammed K., Mentel G., Majewski S., Shahzadi I.

This paper investigates the effect of the circular economy on CO2 emissions growth by considering the role of energy transition, climate policy stringency, industrialization, and supply chain pressure from 1997 to 2020 using panel quantile Autoregressive Distributed Lags (QARDL) and the panel PMG. We employ cointegration association in the long run among the variables, and the results of the two models confirm this. Findings reveal that circular economy and climate policy stringency significantly negatively impact carbon emissions. On the other hand, the energy transition, industrialization, and supply chain pressures are crucial to determining CO2 emissions in the short and long run. The finding further explores that municipal waste generation recycling is considerable at the mean and upper 90th quantiles than the lower quantile. Therefore, the empirical results of the current study provide acumens for policymakers of advanced economies and emerging markets to maintain the balance among circular economy, energy transition, environmental policy stringency, and supply chain pressure for reducing CO2 emissions without halting economic growth and sustainable development. Furthermore, practical implications are reported through the lens of carbon neutrality and structural changes.

Abbas S., Saqib N., Mohammed K.S., Sahore N., Shahzad U.

China is adopting innovative strategies to mitigate the carbon emissions and to enhance environmental sustainability. China's pilot low-carbon city program is a comprehensive program to attain carbon neutrality and green transformation. The current research is an attempt to explore the dynamic relationship between green patents, energy use, research and development (R&D) expenditure, and carbon dioxide emissions of Chinese cities considered for the China Pilot Low Carbon City Program (CPLCCP). The prime objective of current research is to examine the validity of the Environmental Kuznets Curve (EKC) theory in the context of energy use, R&D and green patents. This objective is realized by employing CS-ARDL, Q-ARDL, and Granger's non-causality approach on panel data of 118 Chinese cities for the period of 2003 to 2020. The estimated result reveals that allocating resources towards R&D and green technological innovation can substantially increase environmental sustainability across various quantiles. Furthermore, the empirical findings validate the existence of Environmental Kuznets Curve (EKC) theory. The study suggests fruitful insights for policymakers and stakeholders committed apropos sustainable development and carbon neutrality of China.

Hachemaoui M., Boukoussa B., Mokhtar A., Mekki A., Beldjilali M., Benaissa M., Zaoui F., Hakiki A., Chaibi W., Sassi M., Hamacha R.

Mesoporous silica MCM-41 was synthesized hydrothermally and then impregnated by different transition metals (such as Cr, Cu, Fe and Zn). The modified materials in calcined and non-calcined forms were tested in the adsorption of OG and MB dyes in single and binary system. Effect of calcination, contact time, initial dye concentration and adsorbent mass were studied. Two kinetics models were applied the first and the second order kinetics as well as the Freundlich and Langmuir isotherms were tested. The obtained samples were also used as anti-bacterial and anti-fungal agents using gram negative (P.aeruginos and E coli), gram positive (B. cereus, and S. aureus) pathogenic clinical bacteria and pathogenic fungi (Candida albicans). The result confirms that the adsorption process of both dyes follows second-order kinetics and their equilibrium data were fitted well to the linear Langmuir model. The maximum adsorption capacity of OG and MB dyes was 200 mg/g and 166 mg/g for non-calcined and calcined Zn/MCM-41, respectively. The adsorption of a binary mixture showed that the both materials are selective. The best selectivity was obtained by non-calcined Zn/MCM-41 wherein the OG dye was predominantly adsorbed. The application of all samples as anti-bacterial and anti-fungal agents showed encouraging results, but the best results were obtained by non-calcined materials, particularly with Cu/MCM-41 and Zn/MCM-41.

Marni Sandid A., Bassyouni M., Nehari D., Elhenawy Y.

• Desalination plant was powered by solar energy. • Solar powered membrane-based shows remarkable reducing in carbon dioxide emissions. • The solar desalination systems were numerically simulated. • Significant reduction in fresh water cost using solar membrane distillation. Solar thermal energy for membrane distillation desalination is a green and safe way for areas where water scarcity and solar irradiance are strongly correlated. In this paper, a commercial-scale of desalination plant was installed and tested to study the performance of a multichannel spiral-wound air gap membrane distillation module with an area of 14.4 m 2 . Air gap membrane distillation desalination plant at Port Said university was powered by solar energy using flat plate and evacuated tube collectors. The model validation was carried out. The solar desalination systems were numerically simulated using the program TRNSYS under different weather conditions throughout the year. The influence of the main operating parameters (feed flow rate and inlet temperatures of evaporator and condenser) was investigated. Regression analysis agreed with experimental data fitting using a quadratic polynomial model with coefficients of determination (R 2 ) values of 0.997, 0.972, and 0.999 for permeate flux, outlet feed temperature, and outlet coolant temperature, respectively. The results showed that the permeate flux of the air gap membrane distillation with the evacuated tube collectors was 18.81%–30.44% higher than flat plate collector, and its cost was 22.48% lower. The specific thermal energy consumption of the air gap membrane distillation system ranged from 158.83 kWh/m 3 to 346.55 kWh/m 3 . The maximum gain output ratio reaches 4.4 at 52 °C, depending on the feed inlet temperature. The thermal efficiency of the air gap membrane distillation system is 72%. The proposed air gap membrane distillation system produced 28.78 m 3 /year of fresh drinking water at a cost of USD 14.73/m 3 with remarkable reducing in carbon dioxide emission s by 7,274.45 kg/year.

Hachemaoui M., Mokhtar A., Ismail I., Mohamedi M.W., Iqbal J., Taha I., Bennabi F., Zaoui F., Bengueddach A., Hamacha R., Boukoussa B.

The current study deals with the preparation and development of nanomaterials based on iron, copper, chromium or cobalt to study their antibacterial and catalytic properties. To achieve this, the different metals were dispersed in the material MIL-101(Cr) by an ultrasonic-assisted method and then treated by chemical reduction in order to produce corresponding metal nanoparticles (MNPs). The obtained nanocatalysts MIL-101(Cr)/MNPs were characterized by various techniques such as XRD, XPS, SEM, TEM, FTIR; TGA, XRF, Adsorption-desoprtion of nitrogen at 77 K and UV–vis DR. The results showed that the nanocatalysts consist of a mixture of metal phases and oxides. All the prepared nanocatalysts were evaluated based on their performance in reducing the methylene blue (MB) dye in the presence of NaBH 4 as reducing agent, for selection of the optimal catalyst. The best catalytic activity was obtained by the MIL-101 (Cr)/CuNPs nanocatalyst in which 6 min was sufficient to reduce the MB dye and the recorded rate constant k app was 0.503 min −1 . The performance of this catalyst was evaluated by varying the effects of three important parameters such as catalyst loading and the concentration of NaBH 4 and MB dye. The study of the effects of these three parameters on the reduction process reveals that more than 99% of MB dye was reduced using 0.6 mM of MB dye, 6.8 mM of NaBH 4 and 3 mg of nanocatalyst. The kinetic study shows that the reduction of MB dye by the MOF-101(Cr)/CuNPs nanocatalyst follows pseudo-first order kinetics. In addition, the MIL-101(Cr)/CoNPs and MIL-101(Cr)/CuNPs samples demonstrated efficacy at inhibiting bacterial and fungal growth. Hence, it is concluded through this work that the nature, size and concentration of nanoparticles present in the MOF matrix are the key parameters that can influence the catalytic and antibacterial properties of these MNP-loaded MIL-101(Cr) systems. • Metallic nanoparticles were dispersed on MIL-101(Cr) surface using sonication process. • The obtained nanocatalysts were used for MB dye reduction and pathogenic bacteria elimination. • The MIL-101 (Cr)/CuNPs nanocatalyst showed a high catalytic activity via MB dye. • The highest antibacterial activities of MIL-101(Cr)/CoNPs and MIL-101(Cr)/CuNPs materials was revealed.

Bentout S., Chen Y., Djilali S.

In this paper, we study an SEIR model with both infection and latency ages and also a very general class of nonlinear incidence. We first present some preliminary results on the existence of solutions and on bounds of solutions. Then we study the global dynamics in detail. After proving the existence of a global attractor $\mathcal{A}$ , we characterize it in two cases distinguished by the basic reproduction number $R_{0}$ . When $R_{0}<1$ , we apply the Fluctuation Lemma to show that the disease-free equilibrium $E_{0}$ is globally asymptotically stable, which means $\mathcal{A}=\{E_{0}\}$ . When $R_{0}>1$ , we show the uniform persistence and get $\mathcal{A}=\{E_{0}\}\cup C \cup \mathcal{A}_{1}$ , where $C$ consists of points with connecting orbits from $E_{0}$ to $\mathcal{A}_{1}$ and $\mathcal{A}_{1}$ attracts all points with initial infection force. Under an additional condition, we employ the approach of Lyapunov functional to find that $\mathcal{A}_{1}$ just consists of an endemic equilibrium.