## 1 Introduction  
In the last few years, numerous synthetic drugs have contaminated the aqueous system [1]. Antibiotics are the major problem among these contaminants, as they are highly toxic and widely used for both pets and human medicines [2]. They increase environmental pollution due to their widespread use and toxic nature [3]. Moreover, the presence of these compounds in water supplies, even at low levels, strengthens bacterial resistance, consequently creating antibiotic resistance (ABR) [4]. ABR is the ability to live and to multiply in the presence of antibiotic concentrations, which have previously been thought to be successful against a given bacterium or another microorganism [5]. New research hasfound that antibiotic resistance is responsible for 700,000 deaths per year worldwide [6]. They are now generally recognized as a significant threat to public health [7]. The conventional wastewater treatment techniques cannot effectively eliminate residues of antibiotics from wastewater [8; 9; 10]. Examples of these physical treatment approaches, such as filtration, adsorption, reverse osmosis, and membrane, cannot remove antibiotics totally from wastewater that remains the risk of the cumulative contaminants as an environmental concern. However, it has been emphasized that Advanced Oxidation Processes (AOPs) are a viable alternative to the rapid degradation of non-degradable compounds in water [11; 12; 13; 14]. The heterogeneous photocatalytic technique has especially shown an efficient degradation of various drug forms and organic molecules [15; 16; 17; 18; 19; 20; 21]. It is based on the concept of catalyst activation utilizing energy given by a light source, such as LED, UV, and solar light [22]. Semiconductors are widely used as catalysts, because they are efficient and straightforward to synthesize. The preferred materials for the synthesis of the semiconductors are titanium (Ti), bismuth (Bi), zinc (Zn), and tin (Sn) [23; 24; 25], and as examples, ZnO and TiO\({}_{2}\) semiconductors, which are commonly used. Recently, Bismuth-based semiconductors have become a promising group of developed advanced photocatalytic materials due to their high chemical stability and their excellent transparency for light penetration [26; 27]. Zinc bismuthate with the chemicals formula ZnBi\({}_{2}\)O\({}_{4}\) (ZBO) is a topical semiconductor and promising photocatalyst that has attracted interest among several research groups [26; 28; 29; 30; 31; 32]. That is due to its high stability and small optical band gap around 2.8 eV, making better use of sun-light. In the comparison between ZBO, zinc oxide (ZnO) and bismuth oxide (Bi\({}_{2}\)O\({}_{3}\)), ZnO needs wavelengths below 400 nm for excitation due to its large bandgap, which gives it a low efficient harvester of sunlight, unlike ZBO which has a smaller one. This makes it more active in the sun-light and suitable for high photo-durability in various areas such as optoelectronics and photocatalysis [28; 29]. On the other hand, Bi\({}_{2}\)O\({}_{3}\) exhibits low photocatalytic activity due to the excited electrons from the conduction band (ECB = 0.33 eV) that cannot produce active degradation radicals [33; 34]. Another disadvantage of ZnO and Bi\({}_{2}\)O\({}_{3}\) is that charge carrier recombination of photo-generated electron/hole pairs occurs in nanoseconds promoting photochemical corrosion [35]. In contrast, ZBO has an excellent charge carrier recombination rate, shielding it from photo-oxidation [36]. To our knowledge, this is the first application of ZBO for antibiotics removal. Moreover, there is a lack of studies dealing with the use of ZBO as a photocatalyst and only one study has dealt with the electrochemical characterization of ZBO (only Mott-Schottky characteristic [37]). Moreover, no studies have been carried out yet on the optical and dielectric properties of ZBO.