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Numerous treatment methods such as biological digestion, chemical oxidation, and coagulation have been used to treat organic micropollutants. However, such wastewater treatment methods can be either inefficient, expensive, or environmentally unsound. Here, we embedded TiO2 nanoparticles in laser-induced graphene (LIG) and obtained a highly efficient photocatalyst composite with pollutant adsorption properties. TiO2 was added to LIG and lased to form a mixture of rutile and anatase TiO2 with a decreased band gap (2.90 ± 0.06 eV). The LIG/TiO2 composite adsorption and photodegradation properties were tested in solutions of a model pollutant, methyl orange (MO), and compared to the individual and mixed components. The adsorption capacity of the LIG/TiO2 composite was 92 mg/g using 80 mg/L MO, and together the adsorption and photocatalytic degradation resulted in 92.8% MO removal in 10 min. Adsorption enhanced photodegradation, and a synergy factor of 2.57 was seen. Understanding how LIG can modify metal oxide catalysts and how adsorption can enhance photocatalysis might lead to more effective pollutant removal and offer alternative treatment methods for polluted water. [ABSTRACT FROM AUTHOR]

Laser-induced graphene (LIG) is a method of generating a foam-like conformal carbon layer of porous graphene on many types of carbon-based surfaces. This electrically conductive material has been shown to be useful in many applications (e.g., environmental technology) and exhibits low fouling and antimicrobial surfaces. Moreover, polymers and concrete composite materials have been made. Since LIG is formed using common engraving or cutting lasers, LIG images on paper products was recently termed "graphene art". Here we show that graphene art generated on polymers can be composited and made functional. Pouring concrete on LIG images obtained on poly-(ether sulfone) or polyimide and transferring the LIG onto the set concrete surface by simply peeling off the polymer support resulted in LIG-concrete composite artistic designs. The electrically conductive LIG-concrete composite art was functional and showed antibacterial effects when an electrical potential was applied (i.e., an antimicrobial rate (AR) of 100%a 5 log reduction). These examples show that artistically designed LIG-concrete composites can be functional by utilizing the electrical and chemical properties of LIG and especially for antibacterial effects, which might be of use for incorporation into structural aspects of hospitals or other buildings where sterile surfaces might provide added protection for immune-compromised patients. [ABSTRACT FROM AUTHOR]