Development and characterization of MWCNTs from activated carbon as adsorbent for metronidazole and levofloxacin sorption from pharmaceutical wastewater: Kinetics, isotherms and thermodynamic studies

Efficient removal of antibiotics from water resources is a public health priority: a critical assessment of the efficacy of some remediation strategies for antibiotics in water

This review discusses the fundamental principles and mechanism of antibiotic removal from water of some commonly applied treatment techniques including chlorination, ozonation, UV-irradiation, Fenton processes, photocatalysis, electrochemical-oxidation, plasma, biochar, anaerobicdigestion, activated carbon and nanomaterials. Some experimental shortfalls identified by researchers such as certain characteristics of degradation agent applied and the strategies explored to override the identified limitations are briefly discussed. Depending on interactions of a range of factors including the type of antibiotic compound, operational parameters applied such as pH, temperature and treatment time, among other factors, all reviewed techniques can eliminate or reduce the levels of antibiotic compounds in water to varying extents. Some of the reviewed techniques such as anaerobic digestion generally require longer treatment times (up to 360, 193 and 170 days, according to some studies), while others such as photocatalysis achieved degradation within short contact time (within a minimum of 30, but up to 60, 240, 300 and 1880 minutes, in some cases). For some treatment techniques such as ozonation and Fenton, it is apparent that subjecting compounds to longer treatment times may improve elimination efficiency, whereas for some other techniques such as nanotechnology, application of longer treatment time generally meant comparatively minimal elimination efficiency. Based on the findings of experimental studies summarized, it is apparent that operational parameters such as pH and treatment time, while critical, do not exert sole or primary influence on the elimination percentage(s) achieved. Elimination efficiency achieved rather seems to be due more to the force of a combination of several factors.

Microbial Nanotechnology for Bioremediation of Industrial Wastewater

Pollutant removal from industrial effluents is a big challenge for industries. These pollutants pose a great risk to the environment. Nanotechnology can reduce the expenditure made by industries to mitigate these pollutants through the production of eco-friendly nanomaterials. Nanomaterials are gaining attention due to their enhanced physical, chemical, and mechanical properties. Using microorganisms in the production of nanoparticles provides an even greater boost to green biotechnology as an emerging field of nanotechnology for sustainable production and cost reduction. In this mini review, efforts are made to discuss the various aspects of industrial effluent bioremediation through microbial nanotechnology integration. The use of enzymes with nanotechnology has produced higher activity and reusability of enzymes. This mini review also provides an insight into the advantages of the use of nanotechnology as compared to conventional practices in these areas.

Differentiation Between Metronidazole Residues Disposal by Using Adsorption and Photodegradation Processes Onto MgO Nanoparticles

Background

Metronidazole (MNZ) is an antibiotic form that is considered as a dangerous environmental pollutant due to its widespread use as growth promoters in livestock and aquaculture operations along with its therapeutic application for humans.

Purpose

The objective of this work was to conduct a comparative study between the efficiency of the adsorption and photocatalytic degradation of MNZ in an aqueous solution by using magnesium oxide nanoparticles (MgO NP) under different effects, as well as evaluate the performance, reusability and cost study.

Materials and Methods

Several instruments such as XRD, EDX, SEM, and TEM were used to characterize the chemical composition and morphological properties of the synthesized MgO NP, while the GC-MS analysis was used to monitor the degradation pathway of MNZ particles within 180 min. The simple photo-batch reactor was used to investigate the degradation of MNZ under the effect of UV radiation, initial concentration of MNZ, pH, catalyst loading, inorganic salts addition, time, and temperature.

Results

The degradation efficiency is mainly divided into two steps: 35.7% for maximum adsorption and 57.5% for photodegradation. Adsorption isotherm models confirmed that the process nature is chemisorption and appropriate Langmuir model, as well as to be a nonspontaneous and endothermic reaction according to the thermodynamic study. Adsorption constant during dark condition is smaller than typical adsorption equilibrium constant derived from the Langmuir-Hinshelwood kinetic model through photodegradation of MNZ that follows pseudo-first-order kinetics. Toxicity rates were reduced considerably after the photodegradation process to 88.21%, 79.84%, and 67.32% and 57.45%, 51.98%, and 43.87% by heamolytic and brine shrimp assays, respectively, for initial MNZ concentrations (20, 60, and 100 mg/L).

Conclusion

We significantly recommend using MgO NP as a promising catalyst in the photodegradation applications for other organic pollutants in visible light.