A method for removing arsenic from a liquid includes adding a two-dimensional metal carbide adsorbent to the liquid to adsorb the arsenic from the liquid. The two-dimensional metal carbide adsorbent can include at least one MXene, having the formula Mn+1Xn, where n=1, 2 or 3, where M is an early transition metal, such as scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo) or the like, and X is either carbon or nitrogen. The MXene may be Ti3C2.