Medicinal plants are the product of natural drug discoveries and have gained traction due to their pharmacological activities. Pathogens are everywhere, and they thrive in ideal conditions depending on the nutrients, moisture, temperature, and pH that increase the growth of harmful pathogens on surfaces and textiles. Thus, antimicrobial agents and finishes may be the solution to the destruction of pathogens. This review article presents an analysis of various aspects of producing antimicrobial finishings, the microorganisms, their mechanism of attachment to natural and synthetic fibre, the effect of microbial growth, and the principle and mechanism of the microbial activity of the medicinal plants. Furthermore, the extraction methods, qualitative and quantitative phytochemical evaluations of antimicrobial efficacy, and developments of antimicrobial treated textiles using various agents are covered in this review.

Biogas, a product of anaerobic digestion process that consists mainly of methane and carbon dioxide is a suitable alternative fuel if unwanted impurities are removed as they have a negative impact on the equipment. The most significant technologically troublesome trace compounds that must be removed are siloxanes since they are converted into silica on gas surface engines and turbines resulting in equipment damage. The quality of the gas is certainly improved by reducing the amount of impurities and the end use determines the extent of biogas cleaning needed. The major aim of this study was to compile information that can assist researchers or even designers in selecting a suitable technology to remove siloxanes. Siloxane removal definitely can be achieved using different methods and the effectiveness of each method relies on careful consideration of the characteristics of both biogas and siloxane, as well as the technological aspects of the method. Herein, we review on different cleaning techniques for siloxanes in raw biogas, the negative effects they have, their levels and technologies to reduce their concentrations. This review also incorporates the sources of the siloxanes, the progress to date on their removal and possible ways of regenerating adsorbents. The reviewed literature suggests that biogas upgrading technology should be promoted and encouraged especially in siloxane removal as it has detrimental effects on engines. The parameters and effectiveness of adsorption processes are discussed, and individual adsorbents are compared.

Herein, we report the synthesis of quartz supported TiO₂ photocatalysts codoped with carbon and silver through the hydrolysis of titanium tetrachloride followed by calcination at 500°C. The prepared samples were characterized by UV-Vis diffuse reflectance spectroscopy, high resolution scanning electron microscopy (HRSEM), Raman spectroscopy, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). Codoping of TiO₂ with Ag and carbon resulted in an increase in the surface area of the photocatalyst and altered the ratio of the anatase to rutile phase. The absorption edge of all the doped TiO₂ photocatalysts redshifted and the band gap was reduced. The lowest band gap of 1.95 eV was achieved by doping with 0.5% Ag. Doping TiO₂ using carbon as the only dopant resulted in a quartz supported photocatalyst that showed greater photocatalytic activity towards methyl orange than undoped TiO₂ and also all codoped TiO₂ photocatalysts under visible light irradiation.

The mechanism of bonding in biomass pellets is such a complex event to comprehend, as the nature of the bonds formed between combining particles and their relevance to pellet quality are not completely understood. In this study, pure and blended biomass pellets made from Norway spruce and pea starch were characterized using advanced analytical instruments able to provide information beyond what is visible to the human eye, with intent to investigate differences in bonding mechanism relevant to quality. The results, which were comprehensively interpreted from a structural chemistry perspective, indicated that, at a molecular level, the major disparity in bonding mechanism between particles of the pellets and the quality of the pellets, defined in terms of strength and burning efficiency, were determined by variation in the concentration of polar functional groups emanating from the major organic and elemental components of the pellets, as well as the strength of the bonds between atoms of these groups. Microscopic-level analysis, which did not provide any clear morphological features that could be linked to incongruity in quality, showed fracture surfaces of the pellets and patterns of surface roughness, as well as the mode of interconnectivity of particles, which were evidence of the production of pellets with dissimilarities in particle bonding mechanism and visual appearance.

The waste generated from antibiotics as influents or effluents in important waters from the rivers over their increased usage is quickly leading to societal health problems. To avoid increased accumulation of these antibiotics and their waste matter, new methods and materials are required to solve the problems before escalation. This paper aimed at evaluating treated wastewater effluent quality of three wastewater treatment plants in South Africa’s Vaal Triangle: Sebokeng, Rietspruit, and Leeuwkuil. The influents and effluents were collected and analysed for heavy metals, and eight antibiotic substances for human use (erythromycin, ampicillin, cimethoprim, tetracycline, ciprofloxacin, doxycycline, chloromphemol, and sulfamethoxazol). The physicochemical parameters were also measured and the results showed that Rietspruit influent (Riet IN) had the highest salinity, total dissolved solids (TDS), electrical conductivity (EC), and turbidity. Sebokeng was found to have the lowest values for all the measured parameters except for pH, which was lowest in Leeuwkuil influent (Lee IN). All the antibiotics were below the detection limit in all three wastewater treatment plants (WWTPs), except for sulfamethoxazole. The average concentration of sulfamethoxazole in the influents and effluents for the three investigated WWTPs ranged 39–47.8 ng L-1. The lowest concentrations of magnesium (8.60 mg L-1) and copper (0.054 mg L-1) were found in Rietspruit (Riet MID) and Lee EFF, respectively. Lee IN had the highest concentrations of Na (27.98 mg L-1), K (7.48 mg L-1), Mn (0.249 mg L-1), Cu (0.208 mg L-1), Fe (0.396 mg L-1), Ni (2.271 mg L-1), and Ca (28.60 mg L-1), while Riet IN had the highest Co concentration of 0.324 mg L-1. Sebo EFF and Sebo IN showed 11.82 mg L-1 of Mg and 2.437 mg L-1 of Zn, respectively. The abundance of the metal concentrations follows the order Ca > Na > Mg > K > Zn > Ni > Fe = Pt > Co = Au > Mn > Cu > Cr > As, indicating a higher concentration of Ca as 28.60 mg L-1, while As has the least value, which is 0.053 mg L-1.