That would depend on the pollutant and adsorbent in question. For example, pH affects adsorbate charge, speciation, (i.e. some metal ions may exist as a free metal in solution under acidic conditions, but bind with hydroxides and other anions under alkaline conditions such as precipitation of copper as basic sulfates when sulfate is present). pH can also affect adsorbents by affecting surface charge/zeta potential, while also causing dissolution in some cases.

Temperature is more of a thermodynamic thing, so again it will depend on the specific case being studied. I've seen adsorption capacity increase or decrease as functions of temperatures, the key is to recall that the process thermodynamics are in part governed by the Van't Hoff equation (dG=dH-T*dS=-R*T*ln(K)) so you can think about things in part that way. I wouldn't take it too literally though, adsorption processes can involve many different reactions/mechanisms so it is hard to predict.

Best approach in my experience is to get in the lab and start playing around with things. Enjoy!