Optimized Box-Behnken Design Combined Response Surface Methodology to Determine Calcium and Iron Contents Using Visible, Atomic Emission and Atomic Absorption Spectrophotometry in Vegetables and Wastewater Samples.

BACKGROUND: Calcium and iron are crucial essential minerals. Iron is mainly responsible for transporting oxygen in the body and the immune system. In comparison, calcium's primary function is in human bones and teeth. Due to that, it is vital to quantify the amount in vegetables. OBJECTIVE: Optimization and validation of three analytical procedures, visible, atomic emission spectrophotometry (AES), and atomic absorption spectrophotometry (AAS), were developed to determine calcium and iron in vegetables and wastewater samples using response surface methodology (RSM) via Box-Behnken design (BBD). The design helps to reduce experiment trials with selected variables to find a correlation between them and their respective dependent variables. METHODS: Method I was developed to quantify calcium in vegetables mixed with concentrated 3M HNO3 and heated to reflux as per the BBD. Then it was cooled, filtered, and completed with 3M HNO3 to be carried out utilizing AES and AAS. For method II, vegetables were mixed with nitric acid and sulfuric acid solution with an optimized 5M KSCN solution, which was computed using the AAS and visible spectrophotometry. RESULTS: First, percentage of water content was calculated for all vegetables, higher in malabar spinach and lower in peas. The calcium and iron contents were present within 0.59-2.68 mg and 35.8-211.5 mg, respectively, in 100 g of vegetables. The results showed a higher amount of iron was available in spinach and a lower amount in okra. In contrast, the highest calcium amount was present in broccoli and the lowest amount was in peas. The calcium and iron content were between 0.015-137.25 and 0.01-147.85 µg/mL in the wastewater samples. CONCLUSIONS: These methods can help to determine the amount of calcium and iron for the quality control samples in research and development, food, and the environmental industry. HIGHLIGHTS: Three validated analytical techniques quantify calcium and iron in vegetables and wastewater samples. The RSM-BBD optimized the method and determined its crucial factors.

Polymeric Materials as Potential Inhibitors Against SARS-CoV-2.

Recently discovered SARS-CoV-2 caused a pandemic that triggered researchers worldwide to focus their research on all aspects of this new peril to humanity. However, in the absence of specific therapeutic intervention, some preventive strategies and supportive treatment minimize the viral transmission as studied by some factors such as basic reproduction number, case fatality rate, and incubation period in the epidemiology of viral diseases. This review briefly discusses coronaviruses' life cycle of SARS-CoV-2 in a human host cell and preventive strategies at some selected source of infection. The antiviral activities of synthetic and natural polymers such as chitosan, hydrophobically modified chitosan, galactosylated chitosan, amine-based dendrimers, cyclodextrin, carrageenans, polyethyleneimine, nanoparticles are highlighted in this article. Mechanism of virus inhibition, detection and diagnosis are also presented. It also suggests that polymeric materials and nanoparticles can be effective as potential inhibitors and immunization against coronaviruses which would further develop new technologies in the field of polymer and nanoscience.

Ceramic Microfiltration Membranes in Wastewater Treatment: Filtration Behavior, Fouling and Prevention.

Nowadays, integrated microfiltration (MF) membrane systems treatment is becoming widely popular due to its feasibility, process reliability, commercial availability, modularity, relative insensitivity in case of wastewater of various industrial sources as well as raw water treatment and lower operating costs. The well thought out, designed and implemented use of membranes can decrease capital cost, reduce chemical usage, and require little maintenance. Due to their resistance to extreme operating conditions and cleaning protocols, ceramic MF membranes are gradually becoming more employed in the drinking water and wastewater treatment industries when compared with organic and polymeric membranes. Regardless of their many advantages, during continuous operation these membranes are susceptible to a fouling process that can be detrimental for successful and continuous plant operations. Chemical and microbial agents including suspended particles, organic matter particulates, microorganisms and heavy metals mainly contribute to fouling, a complex multifactorial phenomenon. Several strategies, such as chemical cleaning protocols, turbulence promoters and backwashing with air or liquids are currently used in the industry, mainly focusing around early prevention and treatment, so that the separation efficiency of MF membranes will not decrease over time. Other strategies include combining coagulation with either inorganic or organic coagulants, with membrane treatment which can potentially enhance pollutants retention and reduce membrane fouling.

Preparation of pH-Indicative and Flame-Retardant Nanocomposite Films for Smart Packaging Applications.

There is an increasing demand for sustainable and safe packaging technologies to improve consumer satisfaction, reduce food loss during storage and transportation, and track the quality status of food throughout its distribution. This study reports the fabrication of colorimetric pH-indicative and flame-retardant nanocomposite films (NCFs) based on polyvinyl alcohol (PVA) and nanoclays for smart and safe food packaging applications. Tough, flexible, and transparent NCFs were obtained using 15% nanoclay loading (PVA-15) with superior properties, including low solubility/swelling in water and high thermal stability with flame-retardant behavior. The NCFs showed average mechanical properties that are comparable to commercial films for packaging applications. The color parameters were recorded at different pH values and the prepared NCFs showed distinctive colorimetric pH-responsive behavior during the transition from acidic to alkaline medium with high values for the calculated color difference (∆E ≈ 50). The prepared NCFs provided an effective way to detect the spoilage of the shrimp samples via monitoring the color change of the NCFs during the storage period. The current study proposes the prepared NCFs as renewable candidates for smart food packaging featuring colorimetric pH-sensing for monitoring food freshness as well as a safer alternative choice for applications that demand films with fire-retardant properties.