Activation of oxygen by zero-valent iron (ZVI) to in-situ produce reactive oxidant species (ROS) provides a promising low-carbon and "green" technology for water purification. However, poor ROS yields and easy inactivation limit its engineering application for organic pollutants elimination. Herein, we fabricated a novel Fe-based catalyst with Fe(II)-regenerative surface derived from phosphatized sewage sludge and iron salts. The achieved materials were composed of sludge biochars, Fe