Method for removing hexavalent chromium in wastewater through magnetic adsorbent compounded by chitosan and magnetic biological carbon

The invention discloses a method for removing hexavalent chromium in wastewater through a magnetic adsorbent compounded by chitosan and magnetic biological carbon. The compounded magnetic adsorbent comprises the magnetic biological carbon, and the chitosan is combined on a magnetic biological carbon matrix. The preparation method comprises the following steps: firstly, utilizing FeCl3.6H2O to soak water hyacinth biomass; secondly, performing pyrolysis and calcination on the soaked biomass to obtain the magnetic biological carbon; finally, compounding the chitosan onto the surface of the magnetic biological carbon. The application steps are as follows: adding a composite material into the wastewater containing the hexavalent chromium with the concentration of 20-500 mg/L, wherein the usage amount of the composite material is 1-2 g/L; carrying out an oscillation and adsorption reaction at 10-50 DEG C for a period of time, and then separating the compound from the wastewater with a magnet to finish the removal of hexavalent chromium ions. The method has the advantages of being low in cost, simple in process, high in absorption property, easy in separation process, environmentally-friendly and the like.