In the present work, poly (2-hydroxy ethyl methacrylate) nanoparticles (PHEMA-RR120) attached to Reactive Red 120 were synthesised as an adsorbent for use in the acidic bating process. PHEMA nanoparticles were first derived by emulsion polymerisation without the use of a surfactant. The dye ligand Reactive Red 120 was chemically attached to the PHEMA nanoparticles via a nucleophilic substitution reaction. The bating process of sheep leathers was then carried out separately with PHEMA-RR120 nanoparticles in place of an acidic protease at pH4.5 and pH6 and in place of an alkali protease at pH8 and pH6 to remove globular proteins from among the leather fibres. According to the results, at pH4.5 the COD, BOD, ammonia and nitrogen values of the acidic protease were respectively 9560mg/L, 4550mg/L, 69.1mg/L and 3.8mg/L, while the wastewater values of PHEMA-RR120 nanoparticles were respectively 9003mg/L, 4300mg/L, 66.8mg/L and 3.70mg/L. At pH8, the COD, BOD, ammonia and nitrogen values of alkaline protease were respectively 1543mg/L, 860mg/L, 95.3mg/L and 8.9mg/L, while the wastewater values of PHEMA-RR120 nanoparticles were respectively 1257mg/L, 666mg/L, 95.7mg/L and 7.9mg/L.