Sorption of Copper(II) Ions by Apple Pectin Modified with Organic Pharmacophores

The sorption properties of apple pectin, native and modified by pharmacophores (nicotinic, salycilic, 5-aminosalycilic, and anthroic acids), are investigated with respect to copper(II) ions. It is established that the modified pectin materials retain high sorption ability as a result of introducing functional groups into their structure, which can efficiently bond metal ions. Sorption isotherms of Cu²⁺ ions in the 273–333 K range of temperatures testify to the exothermal character of the process. It is found that the sorption of Cu²⁺ ions by P-SA, P-AA, and P-5ASA complexes is described by the Langmuir equation; for the P-NA complex, it is described by the Freundlich equation.