Synthesis of High Saturation Magnetization Superparamagnetic Fe <sub/>3</sub> O <sub/>4</sub> Hollow Microspheres for Swift Chromium RemovalLiu, Yubiao; Wang, Yongqiang; Zhou, Shaomin; Lou, Shiyun; Yuan, Lin; Gao, Tao; Wu, Xiaoping; Shi, Xiaojing; Wang, Ke · ACS Applied Materials & Interfaces · 2012