Ecofriendly Reduction of Methylene Blue with Polyurethane Catalyst

Table 1

Name of the kinetic models used, mathematical form of the kinetic models, regression coefficient (²), and rate constant () for reduction of MB with CPUF, ascorbic acid, and mixtures of ascorbic acid and Psidium guajava or Citrus limon extracts at temperature .

Sr. no.	Name of the kinetic model used	Mathematical form of the kinetic model	Regression coefficient ()			Rate constant ()
			^a	^b	^c
1.	Zero order	- =	0.8341	0.7157	0.9009	0.0501 mol dm^-3 min^-1	0.0289 mol dm^-3 min^-1	0.0325 mol dm^-3 min^-1
2.	1st order	ln() = -	0.9464	0.8869	0.9356	0.1485 min^-1	0.1048 min^-1	0.0885 min^-1
3.	2nd order	1/ = + 1/0	0.8622	0.7093	0.7992	0.5304 mol^-1 dm^3 min^-1	0.585 mol^-1 dm^3 min^-1	0.3133 mol^-1 dm^3 min^-1

^aReduction of MB in the presence of ascorbic acid and CPUF (0.25 g). ^bReduction of MB in the presence of Citrus limon extract and ascorbic acid (50 : 50) with CPUF (0.25 g). ^cReduction of MB in the presence of Psidium guajava extract and ascorbic acid (50 : 50) with CPUF (0.25 g).