Synthesis and Application of Shape‐Controllable Calcium Peroxide in Sludge Dewatering

ABSTRACT To systematically elucidate the factors governing the purity and morphology of calcium peroxide (CaO 2 ), single‐factor experiments were conducted by regulating key synthesis parameters, including additives (EDTA and PAM) and reaction conditions. The results indicate that additive preregulation combined with controlled reaction conditions enables the targeted synthesis of CaO 2 with distinct morphologies. Under optimized conditions, the purity of EDTA‐regulated CaO 2 (E‐CaO 2 ) and PAM‐regulated CaO 2 (P‐CaO 2 ) reached 94.03 ± 0.29% and 94.15 ± 0.16%, respectively, accompanied by marked improvements in sludge dewatering performance. Scanning electron microscopy revealed that raw CaO 2 suffered from severe agglomeration, whereas E‐ CaO 2 formed well‐dispersed needle‐like rods and P‐CaO 2 exhibited a three‐dimensional wool‐like structure. X‐ray diffraction, Fourier transform infrared spectroscopy, and electron paramagnetic resonance analyses collectively confirmed the formation of crystalline CaO 2 with intact peroxide structures and effective hydroxyl radical (·OH) release capability. In sludge dewatering experiments, the addition of 0.7 g P‐CaO 2 reduced the capillary suction time by 58.70 ± 5.35%. These findings demonstrate that morphology‐controlled CaO 2 crystals represent a promising strategy for enhancing sludge dewatering efficiency and promoting sludge volume reduction.