Effectiveness of Alkali-Acid Treatment in Enhancement the Adsorption Capacity for Rice Straw: The Removal of Methylene Blue Dye

Table 2

The parameters of Langmuir, Freundlich, Tempkin, and Redlich-Peterson isotherms for MB adsorption.

Parameters	RS	ARS	ARS-0.5C-E	ARS-1C-E	ARS-0.5C	ARS-1C	ARS-E
Langmuir
𝑄𝑚 (mg/g)	32.6	62.9	69.0	74.6	95.2	135.1	107.5
𝐾𝐿 (L/g)	0.4453	0.3804	0.2231	0.4012	0.2425	0.1407	0.3432
𝑅𝐿	0.0994	0.0129	0.0219	0.0123	0.0202	0.0343	0.0143
Δ𝐺 (J/mol)	−24.6	−30.0	−28.6	−30.1	−28.8	−27.4	−29.7
𝑅^2	0.9980	0.9895	0.9984	0.9997	0.9946	0.9966	0.9991
Freundlich
𝐾𝐹 (mg/g)/(L/mg)^1/𝑛	2.7	27.1	27.8	35.6	27.2	31.8	45.2
1/𝑛	0.568	0.215	0.233	0.176	0.387	0.358	0.227
𝑅^2	0.9821	0.9925	0.9706	0.8641	0.9547	0.9919	0.9722
Tempkin
𝐵	—*	10.3	9.9	10.9	22.9	27.5	17.0
𝐾𝑇 (L/mol)	—	8.6	25.6	8.8	1.9	1.7	10.5
𝑏𝑇 (J/mol)	—	248.1	257.8	234.5	111.9	93.2	151.0
𝑅^2	—	0.9921	0.9074	0.9358	0.9800	0.9986	0.9943
Redlich-Peterson
𝛽	—	0.7806	0.8215	0.8744	0.6306	0.6421	0.7650
𝐾𝑅 (L/g)	—	0.1364	0.5951	0.0628	0.0129	0.0163	0.0616
𝐴𝑅 (L/mg)	—	8.37 × 10^−3	0.0113	9.95 × 10^−3	8.63 × 10^−3	4.41 × 10^−3	7.60 × 10^−3
𝑅^2	—	0.9993	0.9938	0.9909	0.9762	0.9973	0.9947

—*: not detected.