Environmental factors such as pH and temperature greatly affect the efficiency of phenolic removal from the water system with the use of AgNPs. The pH of the water system affects the surface properties of silver nanoparticles and the chemical state of phenolic compounds . Typically, slightly acidic to neutral conditions (pH 5-7) increases the efficiency of phenol removal . At high pH (basic) phenols tend to ionize into phenolate anions, that has negative charges, as AgNPs often develop negative surface charge, which may cause electrostatic repulsion that reduces adsorption efficiency . Like pH, adsorption, catalytic degradation and photocatalytic degradation of phenolic compounds is highly dependent on temperature. At high temperature the kinetic energy of molecules increases which enhances their interaction with AgNPs . High temperatures with light exposure increase the removal efficiency of photocatalytic degradation of phenol in the water system . However, excessive temperature may destabilize AgNPs which may lead to agglomeration and reduced surface area, thereby lowering efficiency of removal .