The aromatic organoarsenic compounds (e.g., roxsarsone) has been widely used in breeding industry as feed additives in China for decades. Due to its poorly metabolized by livestocks, roxsarsone (ROX) is excreted in original form through animal urine and feces. After being released into environment, ROX can be transformed into carcinogenic inorganic arsenic (As) species via biotic and abiotic reactions in natural environments, which lead to the widespread contamination of farmland soil and aquatic ecosystems. Thus, the exploitation of effective measures for the rapidly and safely elimnation of organoarsenic compounds are of significant urgency. In this study, bi-functionalized sludge-based biochar supported nano zero-valent iron (NZVI-SBC) composites have been successfully synthesized through simply modified liquid phase reduction method. Characterization results (e.g., SEM, TEM and XPS) manifested that NZVI has been succesfully incorporated into the biochar bulk martrix. Adsorption batch experiments revealed that NZVI-SBC has a unexpected higer adsorption capacity (up to 2500 mg/g at 318.15K) than the pristine biochar. Kinectics studies uncovered that removal processes of ROX followed a pseudo-second-order kinetic model, and the adsorption behavior was highly pH dependent. Based on the results of UV-VIS spectra, FTIR, XPS, LC-AFS and UHPLC-QTOF-MS, the synergistic effect of adsorption and degradation was the pivotal factor for the unexpected higher adsorption capacity towards to ROX by NZVI-SBC. In review of all the experiment data, the removal mechanisms are, therefore, speculated that the attack of As-C bond by hydroxyl radical which generated from the NZVI corrosion in aqueous solutions, which determinated the higer removal capacity of NZVI-SBC for ROX. This study demonstrated that NZVI-SBC has great potential for the remediation of organoarsenic compounds contaminated wastewater.