Cu2+ ions were successfully loaded into TiO2 nanotubes using wet impregnation technique in 0.6？M Cu(NO3)2·3H2O solution. The effect of reaction temperatures on the nanotube’s morphology, crystal structure, and their photocatalytic reduction of Pb(II) ions were investigated. The high reaction temperature could improve the crystallinity of anatase phase. However, irregular and corrugated nanotubular surface covered with Cu precipitates was observed. In the present study, incorporation of an optimum content of Cu element (1.3 at%) into TiO2 nanotubes at room temperature has an important function in enhancing the photocatalytic reduction of Pb(II) ions in alkaline condition (pH 11) due to the higher synergistic effects of photocatalytic reaction under UV illumination. The optimum concentration of Pb(II) ions for effective Pb(II) ions removal performance was found in between 20 and 60？ppm. 1. Introduction Nowadays, toxic heavy metals are the major contaminants of electronic waste. It is a well-known fact that those heavy metals are elements having high atomic weights between 63.5 and 200.6 and a specific gravity greater than 5.0 [1]. Heavy metal contaminations in the aquatic environment including arsenic (As), cadmium (Cd), lead (Pb), chromium (Cr), copper (Cu), nickel (Ni), zinc (Zn), and mercury (Hg) pose an ecotoxicological effect to living creatures [2–4]. Some of these heavy metal contaminations come from fertilizer and sewage, but the biggest source is the effluent industrial discharged from various industries such as electronic industry, mining, electroplating, and battery manufacturing [5]. Since heavy metal contaminations cause serious health effect, wastewater regulations were established to minimize human and environmental exposure to hazardous chemical. The summary of various heavy metals and their permitted concentration is shown in Table 1. Table 1: The maximum contaminant level (MCL) standard for the most hazardous heavy metal [ 4]. Among various heavy metal contaminations shown in Table 1, Pb is our special concern due to persistency and recalcitrant of Pb in the environment. According to World Environmental Protection (WEP), Pb accounts for 98% of the total disposal or other releases of persistent, bioaccumulative, and toxic (PBT) chemicals. In addition, US Environmental Protection Agency (EPA) has reported that the disposal or other releases of PBT chemicals increased by 50%, mainly due to increases in Pb and Pb compounds [6]. The total disposal or other releases of Pb and Pb compounds were increased about 51% in 2010. Thus, Pb contaminants
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