Photodegradation of basic red 51 in hair dye greywater by zinc oxide nanoparticles using central composite design

Photocatalytic degradation of triclocarban in aqueous solution using a modified zeolite/TiO2 composite: kinetic, mechanism study and toxicity assessment

The current work aimed to investigate the degradation of the triclocarban (TCC) in aqueous solution using a modified zeolite/TiO₂ composite (MZTC) synthesized by applying the electrochemical anodization (ECA). The synthesis process was conducted at different voltages (10, 40, and 60) V in 1 h and using electrophoresis deposition (EPD) in doping zeolite. The MZTC was covered with the array ordered, smooth and optimum elongated nanotubes with 5.1 μm of the length, 120.3 nm of the inner diameter 14.5 nm of the wall thickness with pure titanium and crystalline titania as determined by FESEM/EDS, and XRD. The kinetic study by following Langmuir-Hinshelwood(L-H) model and pseudo first order, the significant constant rate was obtained at pH 11 which was 0.079 ppm/min, 0.75 cm² of MZTC catalyst loading size achieved 0.076 ppm/min and 5 ppm of TCC initial concentration reached 0.162 ppm/min. The high-performance liquid chromatography (HPLC) analysis for mechanism study of TCC photocatalytic degradation revealed eleven intermediate products after the whole process of photocatalysis. In regard of toxicology assessment by the bacteria which is Photobacterium phosphoreum, the obtained concentration of TCC at minute 60 was less satisfied with remained 0.36 ppm of TCC was detected indicates that the concentration was above allowable level. Where the allowable level of TCC in stream is 0.1 ppm.

New frontiers in the plant extract mediated biosynthesis of copper oxide (CuO) nanoparticles and their potential applications: A review

Copper oxide nanoparticles (CuO NPs) are one of the most widely used nanomaterials nowadays. CuO NPs have numerous applications in biological processes, medicine, energy devices, environmental remediation, and industrial fields from nanotechnology. With the increasing concern about the energy crisis and the challenges of chemical and physical approaches for preparing metal NPs, attempts to develop modern alternative chemistry have gotten much attention. Biological approaches that do not produce toxic waste and therefore do not require purification processes have been the subject of numerous studies. Plants may be extremely useful in the study of biogenic metal NP synthesis. This review aims to shed more light on the interactions between plant extracts and CuO NP synthesis. The use of living plants for CuO NPs biosynthesis is a cost-effective and environmentally friendly process. To date, the findings have revealed many aspects of plant physiology and their relationships to the synthesis of NPs. The current state of the art and potential challenges in the green synthesis of CuO NPs are described in this paper. This study found a recent increase in the green synthesis of CuO NPs using various plant extracts. As a result, a thorough explanation of green synthesis and stabilizing agents for CuO NPs made from these green sources is given. Additionally, the multifunctional applications of CuO NPs synthesized with various plant extracts in environmental remediation, sensing, catalytic reduction, photocatalysis, diverse biological activities, energy storage, and several organic transformations such as reduction, coupling, and multicomponent reactions were carefully reviewed. We expect that this review could serve as a useful guide for readers with a general interest in the plant extract mediated biosynthesis of CuO NPs and their potential applications.

Elimination of rhodamine B from textile wastewater using nanoparticle photocatalysts: A review for sustainable approaches

Rhodamine B (RhB) dye used in the textile industries is associated with carcinogenic and neurotoxic effects with a high potential to cause a variety of human diseases. Semiconductor photocatalysts synthesised through agriculture waste extracts exhibited high efficiency for RhB removal. The current review aimed to explore the efficiency and mechanism of RhB degradation using different photocatalysts that have been used in recent years, as well as the effect of various factors on the removal process. Zinc oxide nanoparticles (ZnO NPs) synthesised from plant extract is the most effective for the RhB degradation with the efficiency reaching 100% after 210 min. The photocatalysis process depends on the pH because pH changes the balance of water dissociation, which impacts the formation of hydroxyl radicals and the surface load of the catalyst. Analysis using Jupyter Notebook revealed a strong correlation between the concentration of ZnO NPs and the photocatalysis efficiency (R = 0.72). These findings reveal that man-sized photocatalysts have a high potential for removing RhB from the wastewater.

Recent Advances in Sensor-Based Detection of Toxic Dyes for Bioremediation Application: a Review

Extensive use of these harmful dyes has resulted in the surplus presence of these emerging pollutants in the environment, thus demanding an instant and sensitive detection method. Various synthetic dyes are illegitimately mixed into food and other consuming items for displaying bright colours that attracts consumers. The synthetic dyes cause a number of environmental health hazards and promote toxicity, mutagenicity and carcinogenicity in humans. Despite these serious health glitches, synthetic dyes are widely used due to their much lower cost. As a result, a faster, more selective and extremely sensitive technology for detecting and quantifying hazardous dyes in trace amount is urgently needed. This topic is currently in its initial phases of development and needs continuous refinements, such as explaining various sensing methods and potential future uses linked with dye detection technologies. The present review encompasses a comprehensive literature survey on detection of dyes and latest progress in developing sensors for dye detection and summarizes different detection mechanisms, including biosensor-, optical- and electrochemical-based sensors. Detection methodologies are examined with a focus on biosensor-based recent advancements in dye detection and the growing demand for more appropriate systems in terms of accuracy and efficiency.

Adsorption of Reactive Red 195 from aqueous medium using Lotus (Nelumbo nucifera) leaf powder chemically modified with dimethylamine: characterization, isotherms, kinetics, thermodynamics, and mechanism assessment

NOVELTY STATEMENT

In the modern era, dyes are inevitable and their surging usage leads to colossal contamination of aqueous streams, thereby threatening both the land and aquatic species. One among such dye is anionic Reactive Red 195 (RR 195), and traceable even at minute concentrations of aqueous streams, posing a severe threat to living species. Moreover, RR 195 is highly recalcitrant offering resistance to biodegradation due to the presence of an azo (-N=N-) group within its structure. Thus, there is a definite need to address the issue of eliminating RR 195 from industrial wastewater effluents. In lieu of this, the primitive objective of this study is to test the effectiveness of the natural adsorbent lotus leaf (Nelumbo nucifera) for the selective sorption of RR 195 from the aqueous stream. Although ample literature is available on the direct utilization of lotus leaf as adsorbent, yet no study was performed on the chemical modification (dimethylamine) of the aforementioned adsorbent. Hence, an attempt has been made in this direction to add a new sorbent into the adsorbents database.