## 3 Results and Discussions
### Adsorption Results
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & & & **350 HSBC** & **350 PSBC** & **700 HSBC** & **700 PSBC** \\ \hline \multirow{8}{*}{hydrolysis urine} & pseudo-first-order & K\({}_{1}\) (h\({}^{-1}\)) & 0.0103 & 0.0074 & 0.1768 & 0.3285 \\  & pseudo-first-order & Q\({}_{e}\) (mg.g\({}^{-1}\)) & 1.33 & 0.82 & 32.07 & 22.91 \\  & & R\({}^{2}\) & 0.6946 & 0.5277 & 0.8358 & 0.8268 \\  & & K\({}_{2}\) (g\(\cdot\)mg\({}^{-1}\)\(\cdot\)h\({}^{-1}\)) & 0.0047 & 0.0036 & 0.0094 & 0.0230 \\  & pseudo-second-order & Q\({}_{e}\) (mg.g\({}^{-1}\)) & 1.84 & 1.32 & 33.69 & 24.1603 \\  & & R\({}^{2}\) & 0.6968 & 0.5274 & 0.9212 & 0.9273 \\  & & A (mg.g\({}^{-1}\)\(\cdot\)h\({}^{-1}\)) & 1.0982 & 0.9730 & 4.3268 & 21.0282 \\  & & B (g\(\cdot\)mg\({}^{-1}\)) & 0.2578 & 0.1603 & 4.4199 & 2.8414 \\  & & R\({}^{2}\) & 0.7962 & 0.6349 & 0.9967 & 0.9985 \\  & & K\({}_{1}\) (h\({}^{-1}\)) & 1.8004 & 0.1634 & 0.1337 & 0.1879 \\  & pseudo-first-order & Q\({}_{e}\) (mg.g\({}^{-1}\)) & 4.23 & 4.0481 & 39.53 & 30.95 \\  & & R\({}^{2}\) & 0.7737 & 0.9547 & 0.8551 & 0.7827 \\  & & K\({}_{2}\) (g\(\cdot\)mg\({}^{-1}\)\(\cdot\)h\({}^{-1}\)) & 0.0054 & 0.0540 & 0.0054 & 0.0111 \\ PBS & pseudo-second-order & Q\({}_{e}\) (mg.g\({}^{-1}\)) & 4.5474 & 4.3216 & 41.76 & 32.35 \\  & & R\({}^{2}\) & 0.8958 & 0.9254 & 0.9257 & 0.8843 \\  & & \(\alpha\) (mg.g\({}^{-1}\)\(\cdot\)h\({}^{-1}\)) & 1.5678 & 7.4423 & 1.9781 & 5.9534 \\  & & \(\beta\) (g\(\cdot\)mg\({}^{-1}\)) & 0.0442 & 0.6772 & 5.7309 & 4.1451 \\  & & R\({}^{2}\) & 0.8827 & 0.8508 & 0.9930 & 0.9884 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Parameters of pseudo-first-order, pseudo-second-order and Elovich for SMX adsorption by 700 HSBC, 700 PSBC, 350 HSBC and 350 PSBC, respectively. A comparable trend was observed in the adsorption of SMX onto the BCs in the PBS solution, with the fitting trend remaining consistent (Figure 6b). However, it is evident that SMX adsorption in the PBS solution markedly surpassed that in the hydrolysis urine. The SMX removal rate in the PBS by the biochars was significantly higher than that in the hydrolysis urine. As shown in Figure 7, the SMX removal rate could be improved by 20% for high temperature biochar while only 9% improvement was achieved by low temperature biochar. This discrepancy suggests that the ions present in the urine may exert a detrimental effect on the adsorption of SMX onto the BCs. The findings from the rapid adsorption of SMX onto various biochar samples and the associated factors, such as specific surface area and pore structure, underline the potential practical application of biochar in wastewater treatment. The observed differences in  
Figure 6: SMX adsorbed onto the 700 HSBC, 700 PSBC, 350 HSBC and 350 PSBC, respectively, in the synthetic urine (**a**) and PBS solution (**b**). Figure 7: SMX removal rate by the 700 HSBC, 700 PSBC, 350 HSBC and 350 PSBC, respectively, in the synthetic urine and PBS solutions. adsorption capacity among the biochar samples emphasize the need for a thorough understanding of their surface properties when considering their implementation in treatment processes. Moreover, the superior performance of 700 HSBC, attributed to its pore volume roughness enhancing the interaction with SMX, provides insight into the economic aspects of biochar application. By optimizing the selection of biochar types based on their surface characteristics, the efficiency of SMX removal can be maximized, thus potentially reducing the overall costs of wastewater treatment. Furthermore, the influence of solution chemistry, as evidenced by the difference in SMX adsorption between PBS solution and hydrolysis urine, highlights the necessity to account for the composition of the wastewater being treated. Considering the potential detrimental effect of urine ions on SMX adsorption onto biochar, economic analyses should encompass the costs associated with adjusting treatment processes to accommodate varying wastewater compositions.