Photocatalytic Degradation of Organic Dyes and Antimicrobial Activities by Polyaniline–Nitrogen-Doped Carbon Dot Nanocomposite

Abstract

Nitrogen-doped carbon nanodots (N@CDs) were prepared by hydrothermal processing of bovine serum albumin (Mw: 69,324 with 607 amino acids). A polyaniline (PANI-N@CDs) nanocomposite was then synthesized by ultrasonication and used to degrade Congo red (CR), methylene blue (MB), Rhodamine B (RhB), and crystal violet (CV) four common organic dyes. The PANI-N@CD nanocomposite simultaneously adsorbed and concentrated the dye from the bulk solution and degraded the adsorbed dye, resulting in a high rate of dye degradation. The combination of holes (h+), hydroxyl (OH•), and O2•− was involved in the N@CD-mediated photocatalytic degradation of the dyes. Under visible light illumination at neutral pH, the PANI-N@CDs were proven as an efficient adsorbent and photocatalyst for the complete degradation of CR within 20 min. MB and RhB were also degraded but required longer treatment times. These findings supported the design of remediation processes for such dyes and predicted their fate in the environment. The nanocomposite also exhibited antimicrobial activities against Gram-negative bacterium E. coli and Gram-positive bacterium S. aureus.

{BW12O40} Hybrids Modified by in Situ Synthesized Rigid Ligand with Supercapacitance and Photocatalytic Properties

“…It is recognized that the growth of photocatalysis, especially for the abatement or removal of organic pollutants from wastewater, is of great significance for environmental protection. − In recent decades, much focus has been placed on the application of POMs and related composites in the photocatalytic degradation of organic dyes. − RhB and MB are representative organic dye contaminants, and therefore, these two dyes are harnessed to demonstrate the photocatalytic properties of compounds 1 and 2 under UV irradiation; see Figures S21 and S22. Photocatalytic experiments revealed that compounds 1 and 2 displayed 91.28% and 92.58% RhB degradation efficiency (1 – C t / C 0 ) (where C t is the concentration of the dye after the photocatalytic degradation has proceeded for a certain period of time, and C 0 is the initial concentration of the dye before the photocatalytic degradation) after 150 min, respectively (Figure a).…”

Carbon Dots as an Emergent Class of Antimicrobial Agents

“…These composites have found ample antibacterial applications (such as in water treatment [126][127][128][129] and the surface coating field [130][131][132]). In many cases, the CD-composites showed bactericidal activity upon sun light illumination [133][134][135][136]. It is worth noting that the use of metal-based composites for antibacterial applications may be counterbalanced by the inherent environmental and eukaryotic cellular toxicity of transition metals derivatives that should be taken into account to exclude off target effects [137][138][139][140].…”

Recent Advances in the Removal of Organic Dyes from Aqueous Media with Conducting Polymers, Polyaniline and Polypyrrole, and Their Composites

“…The organic substrates coated with conducting polymers include synthetic polymers, such as carboxymethylcellulose gel [ 78 ], Kevlar fibers [ 73 ], macroporous melamine sponges [ 16 ], poly(ethylene oxide) [ 76 ], polyimide membrane [ 74 ], polystyrene [ 64 ], poly(vinyl alcohol) aerogel [ 42 ], polyurethane foam [ 77 ], and various natural materials, such as [ 24 , 75 ], chitosan [ 82 ], opuntia ficus [ 80 ], almond and wall nut shells [ 81 ] or tea saponin [ 41 ]. Only exceptionally, both components were simply mixed, e.g., polyaniline and nitrogen-containing carbon nanodots [ 87 ] or zinc oxide [ 61 ]. In this case, the fact that the organic component may also be an efficient adsorbent in addition to conducting polymer also has to be kept in mind [ 16 ].…”

“…On rare occasions, polyaniline was simply mixed with an inorganic compound. The mixture of polyaniline and nitrogen-containing carbon nanodots, obtained by the hydrothermal method from bovine serum albumin, photocatalyzed the decomposition of various dyes [ 87 ]. A mixture of commercial polyaniline with nickel tungstate was used to decompose methylene blue and crystal violet [ 111 ].…”

“…The antibacterial activity of the polyaniline composites has occasionally been mentioned [ 56 , 75 , 78 , 101 ]. This may be expected, especially in photocatalytic experiments, due to the formation of reactive oxygen species [ 87 , 119 , 120 ].…”