Arsenic (As) poisoning in water is a critical global problem. Current arsenic removal techniques involving chemical reaction, ion exchange, or membrane processes can be expensive, inaccessible, or infeasible for underdeveloped regions. Here, we demonstrate that by using a so-called a directional solvent extraction (DSE) process arsenic ions in water can be effectively removed without membrane or chemical reaction, and this process promises to utilize low temperature heat (as low as 45 degrees C). We have tested feedwater with different arsenic concentrations and arsenic ions in different forms (As-III and As-V) commonly found in nature. It is demonstrated that DSE using decanoic acid as the directional solvent can purify contaminated water to meet the drinking water standard (arsenic concentration <10 parts per billion, ppb), and the arsenic removal efficiencies are higher than 91% for As-III and 97% for As-V. DSE can potentially lead to effective arsenic removal technologies with low resource settings.