The surface of nano-TiO2 was modified by a silane coupling agent KH570, and the photosensitive resin was modified by blending the modified nano-TiO2 with three-dimensional (3D) printing light-curing resin. The modified nano-TiO2 powder was characterized by infrared spectrum, X-ray diffraction, contact angle test, and scanning electron microscope. The effects of different content of modified TiO2 on the viscosity, curing shrinkage, tensile strength, elongation at break, hardness, thermal stability, and cross-section morphology of 3D printing photosensitive resin were studied. The results showed that the mechanical properties of epoxy resin were improved obviously after surface modification with a silane coupling agent. When the mass fraction of TiO2 was 1.5%, the mechanical properties of the molded parts were the best. The tensile strength, impact strength, and elongation at break were increased by 51.1, 43.8, and 10.8%, respectively, and the hardness value was maintained at 81–83 HD. The addition of modified TiO2 can improve the heat resistance of the epoxy resin. When the amount of TiO2 is 1.5%, the T 50%, T max, and carbon residue rate of the epoxy resin are increased by 3.44°C, 6.34°C, and 25.3%, respectively.

Removal of Cu2+ ions from contaminated water is an important but challenging task. This study reports the synthesis of a composite hydrogel from two natural polysaccharides, namely, sodium alginate and chitosan, using inexpensive kaolin as a raw material and polyacrylamide as a modifier. The hydrogel had a high adsorption capacity and selectivity for Cu2+. The composite hydrogel was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The pseudo-second-order kinetic model was the most suitable model for the kinetic results, and the Langmuir isotherm model was the most representative of the sorption system. The results revealed that the adsorption process was mainly controlled by chemisorption. The maximum adsorption capacity of the adsorbent was 106.4 mg·g−1. Therefore, this study presents a new perspective on the application of composite hydrogels as Cu2+ adsorbents.