Adsorption and Photocatalytic Decomposition of the 𝛽-Blocker Metoprolol in Aqueous Titanium Dioxide Suspensions: Kinetics, Intermediates, and Degradation Pathways

Table 1

Isotherm parameters for MET adsorption onto TiO₂ obtained by linear method at 25°C.

Two-parameter model	Parameters	pH
		Free	9
Langmuir; 𝑞𝑒=𝑞𝑚𝐾𝑎𝐶𝑒1+𝐾𝑎𝐶𝑒	𝑞𝑚 (mol g^−1)	0.0014	0.0250
	𝐾𝐿 (L mol^−1)	0.0930	0.0817
	𝑅^2	0.987	0.998
Freundlich; 𝑞𝑒=𝐾𝐹𝐶𝑒^1/𝑛	1/𝑛	0.244	0.670
	𝐾𝐹 (L mol^−1)	0.00042	0.00129
	𝑅^2	0.105	0.147
Temkin; 𝑞𝑒=𝑅𝑇𝑏ln𝐾𝑇+𝐶𝑒	𝑅𝑇/𝑏	0.00024	0.00508
	𝐾𝑇  (L mol^−1)	2.718	0.962
	𝑅^2	0.604	0.982
Dubinin-Radushkevich; 𝑞𝑒=𝑞𝐷exp−𝐵𝑑1𝑅𝑇ln1+𝐶𝑒	𝑞𝐷 (mol g^−1)	0.0013	0.0233
	𝐵𝐷×10^−3 (mol^2 kJ^−2)	1.533	1.532
	𝑅^2	0.835	0.778
Three-parameter model
Redlich-Peterson; 𝑞𝑒=𝐾RP𝐶𝑒1+𝑎𝑅𝐶𝑒^𝛽	𝐾RP (L mol^−1)	0.00011	0.10
	𝑎𝑅(L mol^−1)	0.051	18.040
	𝛽	0.999	0.679
	𝑅^2	0.826	0.789
Langmuir-Freundlich; 𝑞𝑒=𝐾LF𝐶^𝑛LF𝑒1+𝑎LF𝐶𝑒^𝑛LF	𝐾LF (L mol^−1)	0.000205	0.00809
	𝑎LF (L mol^−1)	0.134	0.310
	𝑛LF	0.779	0.92
	𝑅^2	0.211	0.734