## 5 Conclusions  
This study highlights the impact of temperature on the removal efficiency of selected inorganic contaminants typical for stormwater on activated carbon and low-cost mineral adsorbents (diatomite, halloysite, limestone sand and zeolite). The investigation revealed that ambient temperature determining the conditions in the sub-surface soil layer, and therefore, in the sub-surface permeable treatment zone, may influence the removal of contaminants transported with stormwater from urban areas. The sorption efficiency of the studied materials (activated carbon, diatomite, halloysite, limestone sand and zeolite) became weaker with decreasing temperature, particularly for heavy metals (from 28% to 46%) compared to biogenic substances (from \(-\)7% to 32%). However, the basic restriction of practical application of the obtained results is the use of mono-component model solutions instead of real stormwater samples. The presence of other dissolved components, competing for active locations on the surfaces of reactive materials, as well as organic matter and suspensions may influence the actual sorption abilities of the materials. In turn, the achievement of this research was to gain a better understanding of how the changes of temperature may affect the removal of heavy metals (Cu and Zn) and nutrients (NH\({}_{4}\)-N and PO\({}_{4}\)-P) from solutions being in contact with selected reactive materials. It has been revealed that the intensity of contaminant removal variably changed with temperature depending on the reactive material and the contaminant; however, analysis of the correlation has shown a positive dependence between these two variables. The test results demonstrated that in conditions of low initial concentrations this correlation is true for heavy metals in the tested range of temperatures (from 3 \({}^{\circ}\)C to 40 \({}^{\circ}\)C) and for biogenes in the range of 3 \({}^{\circ}\)C to 22 \({}^{\circ}\)C. Further increase of temperature caused the decrease of equilibrium sorption capacity of all materials tested. The only exception was the removal of ammonium ions on limestone sand. The investigations provided a conclusion that the decrease of temperature had the greatest impact on the maximum adsorption capacities for copper, followed by zinc and ammonium (on zeolite). Moreover, the values of the analyzed parameter (\(Q_{max}\)) were slightly influenced by temperature changes for phosphate removal on all analyzed reactive materials, as well as ammonium ion removal on halloysite, limestone sand, activated carbon and diatomite. Furthermore, it is worth noting that temperature decrease more significantly reduced the sorption capacities of reactive materials in high concentration solutions. Unfortunately, analysis of the results of the performed investigations precludes defining a universal concentration range for all reactive materials, for which the impact of the analyzed factor may be avoided. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Material**} & \multicolumn{6}{c}{**Treated Contaminants Load (mg/g)**} \\ \cline{2-7}  & \multicolumn{2}{c}{**Cu**} & \multicolumn{2}{c}{**Zn**} & \multicolumn{2}{c}{**NH\({}_{4}\)-N**} & \multicolumn{2}{c}{**PO\({}_{4}\)-P**} \\ \cline{2-7}  & **3 \({}^{\circ}\)C** & **40 \({}^{\circ}\)C** & **3 \({}^{\circ}\)C** & **40 \({}^{\circ}\)C** & **3\({}^{\circ}\)C** & **22 \({}^{\circ}\)C** & **3 \({}^{\circ}\)C** & **22 \({}^{\circ}\)C** \\ \hline Halloysite & 0.90 & 3.32 & 1.55 & 3.36 & 2.20 & 0.68 & 1.10 \\ Limestone sand & 0.90 & 4.28 & 3.80 & - & 2.00 & 0.60 \\ Zeolite & 1.35 & 4.05 & 1.58 & 4.18 & \(>\)3.00 & 0.60 \\ Activated carbon & 2.45 & 7.12 & 3.30 & 3.65 & 1.80 & 1.97 & 1.12 & 1.60 \\ Diatomite & 1.22 & 3.13 & 1.50 & 3.83 & 2.00 & 0.74 & 0.93 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Values of contaminants load treated. The performed studies indicate that the material showing the highest efficiency of Cu and PO\({}_{4}\)-P removal is activated carbon, of Zn is limestone sand, and of NH\({}_{4}\)-N is zeolite.