Synthesis and Characterisation of Activated Carbon Obtained from Marula (Sclerocarya birrea) Nutshell

Table 5

Physicochemical characterisation of the synthesised high carbon samples.

Temperature (°C)	Acid (%)	Physicochemical properties
		pH	Moisture (%)	Ash (%)	Bulk density (g/cm^3)	Iodine value (mg/g)
H2SO4treatments:
200	20	2.9 ± 0.1^a	2.4 ± 0.2^a	0.65 ± 0.01^a	0.62 ± 0.02^c	1036.1 ± 0.01^c
	40	3.9 ± 0.1^b	1.3 ± 0.1^a	3.49 ± 0.01^b	0.53 ± 0.01^a	938.5 ± 0.11^a
	60	2.4 ± 0.1^a	10.7 ± 0.2^c	0.97 ± 0.01^a	0.54 ± 0.02^a	947.4 ± 0.12^a
400	40	6.1 ± 0.1^c	3.9 ± 0.1^b	51.0 ± 0.01^c	0.43 ± 0.01^a	1024.3 ± 0.10^c
	20	5.7 ± 0.1^c	2.8 ± 0.2^a	3.79 ± 0.01^b	0.42 ± 0.01^a	1036.1 ± 0.12^c
	40	5.7 ± 0.1^c	3.3 ± 0.1	4.62 ± 0.2^b	0.43 ± 0.02^a	915.2 ± 0.01^a
500	60	6.1 ± 0.1^c	2.5 ± 0.2^a	4.53 ± 0.01^b	0.45 ± 0.01^a	990.8 ± 0.15^a
value		<0.05	<0.05	<0.05	<0.05	<0.05
H3PO4treatments:
200	60	2.8 ± 0.1^a	6.4 ± 0.2^a	14.2 ± 0.01^a	0.54 ± 0.01^a	1042.6 ± 0.10^a
400	20	3.2 ± 0.1^b	6.6 ± 0.1^a	14.2 ± 0.01^a	0.42 ± 0.02^a	1048.3 ± 0.14^a
500	40	2.7 ± 0.1^a	14.6 ± 0.1^b	29.8 ± 0.01^b	0.82 ± 0.01^b	1075.7 ± 0.11^a
600	20	3.2 ± 0.^b	4.7 ± 0.2^a	11.3 ± 0.01^a	0.39 ± 0.02^a	1131.9 ± 0.13^b
value		<0.05	<0.05	<0.05	<0.05	<0.05

Mean ± standard deviations are reported. Means in a column with different superscripts (^{a, b, c}) are significantly different at .