Rapid Preparation of Biosorbents with High Ion Exchange Capacity from Rice Straw and Bagasse for Removal of Heavy Metals

Table 3

Reaction conditions for preparations of modified rice straw, phosphorus content, degree of substitution, and ion exchange capacity of the modified rice straw.

Sample names	Heating methods	Conditions	% P	Degree of substitution	Ion exchange capacity (meq/g)
Bagasse*	—	—	—	—	0.11*
Bagasse oil 2 hr	Oil bath	150°C 120 min	2.90	0.16	0.86
Bagasse 300 W	Microwave	300 W 5 min	4.04	0.24	1.51
Bagasse 450 W	Microwave	450 W 3 min	4.70	0.28	2.17
Bagasse 600 W	Microwave	600 W 2 min	3.82	0.22	1.36
Bagasse 800 W	Microwave	800 W 1.5 min	2.63	0.15	0.85
Bagasse DMF oil 2 hr	Oil bath	150°C 120 min	0.95	0.05	0.25
Bagasse-DMF 300 W	Microwave	300 W 5 min	3.37	0.19	1.26
Bagasse-DMF 450 W	Microwave	450 W 3 min	4.83	0.29	1.83
Bagasse-DMF 600 W	Microwave	600 W 2 min	4.64	0.28	1.60
Bagasse-DMF 800 W	Microwave	800 W 1.5 min	4.58	0.27	1.59
Bagasse-NaOH oil 2 hr	Oil bath	150°C 120 min	2.61	0.32	1.23
Bagasse-NaOH 300 W	Microwave	300 W 5 min	5.81	0.36	2.38
Bagasse-NaOH 450 W	Microwave	450 W 3 min	7.19	0.46	3.50
Bagasse-NaOH 600 W*	Microwave	600 W 2 min	7.76	0.51*	3.62*
Bagasse-NaOH 800 W	Microwave	800 W 1.5 min	6.89	0.44	3.08

∗Samples for sorption test.