186
Table 4.122: Dubinin Rudushkevich Adsorption Isotherm Constants for SSAC
S/N AC Type Equation
(Y=)
R2 Kad
(mol2/kJ2)
qs
mg/g
qe mg/g (exp)
E
(J/mol)
1 Ni SSAC 6000C HCl 479x-4.548 0.089 479.00 0.01 0.05 0.03 2 Ni SSAC 6000C H3PO4 332.9x-3.662 0.263 332.90 0.03 0.07 0.04 3 Ni SSAC 6000C H2SO4 1022x-5.524 0.640 1022.00 0.00 0.07 0.02 4 Ni SSAC 8000C HCl 776.8x-4.882 0.939 776.80 0.01 0.11 0.03 5 Ni SSAC 8000C H3PO4 -670.5x-1.822 0.456 -670.50 0.16 0.07 0.00 6 Ni SSAC 8000C H2SO4 480.2x-4.089 0.244 480.20 0.02 0.13 0.03 7 Pb SSAC 6000C HCl y = x 1.000 y = x 1.00 0.52 0.00 8 Pb SSAC 6000C H3PO4 -12.72x-1.477 0.101 -12.72 0.23 0.27 0.00 9 Pb SSAC 6000C H2SO4 28.23x-2.327 0.588 28.23 0.10 0.19 0.13 10 Pb SSAC 8000C HCl -167x-1.855 0.549 -167.00 0.16 0.11 0.00 11 Pb SSAC 8000C H3PO4 33.29x-2.966 0.060 33.29 0.05 0.09 0.12 12 Pb SSAC 8000C H2SO4 -24.19x-3.067 0.004 -24.19 0.05 0.08 0.00 13 Cd SSAC 6000C HCl -352.5x-2.872 0.009 -352.50 0.06 0.04 0.00 14 Cd SSAC 6000C H3PO4 -0.984x-3.304 0.040 -0.98 0.04 0.06 0.00 15 Cd SSAC 6000C H2SO4 2079x-8.348 0.321 2079.00 0.00 0.04 0.02 16 Cd SSAC 8000C HCl 1051x-6.027 0.515 1051.00 0.00 0.04 0.02 17 Cd SSAC 8000C H3PO4 2419x-9.153 0.857 2419.00 0.00 0.04 0.01 18 Cd SSAC 8000C H2SO4 1013x-6.199 0.051 1013.00 0.00 0.04 0.02 19 Mn SSAC 6000C HCl 28.35x-3.099 0.233 28.35 0.05 0.69 0.13 20 Mn SSAC 6000C H3PO4 -0.12x+0.129 0.761 -0.12 1.14 1.33 0.00 21 Mn SSAC 6000C H2SO4 -0.418x+0.12 0.524 -0.42 1.13 1.23 0.00 22 Mn SSAC 8000C HCl 880.7x-3.961 0.228 880.70 0.02 0.06 0.02 23 Mn SSAC 8000C H3PO4 -554.2x-2.404 0.417 -554.20 0.09 0.11 0.00 24 Mn SSAC 8000C H2SO4 491.3x-3.202 0.042 491.30 0.04 0.14 0.03
187
From Table 4.131 as well as from Figure 4.131, it could be deduced that carbonization at 6000C gave a better percentage adsorption compare to those of 8000C irrespective of the activating agents.
Figure 4.132: Percentage Adsorption of Cd by OBAC
In the adsorption of Cd by the OBAC, there was a better adsorption by those carbonized at 6000C since most of the percentage adsorption are higher than those of their counter parts except for some that were activated with HCl (Table 4.124 and Figure 4.132).
Figure 4.133: Percentage Adsorption of Pb by OBAC
In Table 4.125 Pb adsorbed better in OBAC carbonized at 8000C and as well had a high percentage of adsorption. This is shown pictorially by Figure 4.133.
0 50 100
1 2 3 4 5
% Adsorption
Activated Carbon Type & IMC
IMC HCl/600˚C HCl/800˚C H2SO4/600˚C H2SO4/800˚C H3PO4/600˚C
0 20 40 60 80 100
1 2 3 4 5
% Adsorption
Activated Carbon Type & IMC
IMC HCl/600˚C HCl/800˚C H2SO4/600˚C H2SO4/800˚C H3PO4/600˚C
188
Figure 4.134: Percentage Adsorption of Mn by OBAC
Just like Pb adsorption by OBAC, Mn was adsorbed better by those carbonized at 8000C even though the percentage adsorption was not that high (Table 4.126).
Tables 4.127 – 4.130 and Figures 4.134 – 4.138 presents the percentage adsorption of Ni, Pb, Cd and Mn respectively on PNAC.
Figure 4.135: Percentage Adsorption of Ni by PNAC
From Table 4.127 and Figure 4.135 which is the percentage adsorption of Ni by PNAC, Ni adsorption by those activated with HCl and carbonized at 6000C were better adsorbent, so also it was for those activated with H2SO4 and H3PO4 except for few of them.
Figure 4.136: Percentage Adsorption of Pb by PNAC
Table 4.128 shows the percentage adsorption of Pb by peanut seed activated carbon.
It could be deduced from this Table that those carbonized at 600oC was better than
0 50 100 150
1 2 3 4 5
% Adsorption
Activated Carbon Type & IMC
IMC HCl/600˚C HCl/800˚C H2SO4/600˚C H2SO4/800˚C
0 10 20 30 40 50 60 70
1 2 3 4 5
% Adsorption
Activated Carbon Type & IMC
IMC HCl/600˚C HCl/800˚C
H2SO4/600˚C H2SO4/800˚C H3PO4/600˚C
0 20 40 60 80 100
1 2 3 4 5
% Adsorption
Activated Carbon Type & IMC
IMC HCl/600˚C HCl/800˚C H2SO4/600˚C H2SO4/800˚C H3PO4/600˚C
189
their counterpart except for 93.6% and 98.8% for HCl activated carbons that were carbonized at 800oC. This can easily be seen in Figure 4.136.
Figure 4.137: Percentage Adsorption of Cd by PNAC
In the adsorption of Cd by the Pear nut seed activated carbon, those carbonized at 800oC and activated with H2SO4 and H3PO4 were better adsorbents in most of the produced activated carbon as indicated by the percentage values of the adsorption.
Generally they all had low percentage of adsorption since their values ranged between 3.4% to 62.1% except for the carbonization at 800oC with H2SO4 activation (Table 4.129 and Figure 4.137).
Figure 4.138: Percentage Adsorption of Mn by PNAC
The percentage Mn adsorption by PNAC as shown in Table 4.130 and Figure 4.138 indicated that those carbonized at 800oC were mostly better than their counterpart except for all those activated with HCl, 7.1% for those activated with H2SO4 and 46.4%, 12.3% for those activated with H3PO4. In general, their overall adsorptions were of average values.
0 50 100
1 2 3 4 5
% Adsorption
Activated Carbon Type & IMC
IMC HCl/600˚C HCl/800˚C H2SO4/600˚C H2SO4/800˚C H3PO4/600˚C
0 50 100 150
1 2 3 4 5
% Adsorption
Activated Carbbon Type & IMC
IMC HCl/600˚C HCl/800˚C H2SO4/600˚C H2SO4/800˚C H3PO4/600˚C
190
Tables 4.131 – 4.134 and figures 4.139 – 4.142 outlined the percentage adsorption
of Ni, Pb, Cd and Mn respectively on PKAC.
Figure 4.139: Percentage Adsorption of Ni by PKAC
The adsorption by palm Kernel shell activated carbon where generally of average and those carbonized at 800oC had a better percentage adsorption especially for the H2SO4 and HCl, but in the case of H3PO4 activated carbon, the reverse was the case in all the respective initial metal concentration (Table 4.131, Figure 4.139).
Figure 4.140: Percentage Adsorption of Pb by PKAC
From Table 4.132 and Figure 4.140, the PKAC activated with HCl and carbonized at 600oC were better adsorbent for Pb while for those activated with H2SO4 and H3PO4, and carbonized at 800oC were better adsorbents. Generally, they all had a high percentage of adsorption except for few.
0 50 100
1 2 3 4 5
% Adsorption
Activated Carbon Type & IMC
IMC HCl/600˚C HCl/800˚C H2SO4/600˚C H2SO4/800˚C H3PO4/600˚C
0 50 100
1 2 3 4 5
% Adsorption
Activated Carbon Type & IMC
IMC HCl/600˚C HCl/800˚C H2SO4/600˚C H2SO4/800˚C H3PO4/600˚C
191
Figure 4.141: Percentage Adsorption of Cd by PKAC
In the adsorption of Cd by PKAC, those carbonized at 600oC had a better percentage adsorption in all except for 86.4%, 91.9% for those activated with H2SO4
and 84.9%, 72.7% for those activated withH3PO4. Also the percentage adsorption of the Cd was generally high (Table 4.133 and Figure 4.141).
Figure 4.142: Percentage Adsorption of Mn by PKAC
The palm kernel AC had a high percentage adsorption of Mn almost in all, but those carbonized at 600oC were better of except 95.7% for those activated with HCl, 60.1% for those activated with H2SO4 and 53.3% for those activated with H3PO4
(Table 4.134, Figure 4.142). Tables 4.136 – 4.138 and Figures 4.143 – 4.146 presented the percentage adsorption of Ni, Pb, Cd and Mn onto SSAC.
Figure 4.143: Percentage Adsorption of Ni by SSAC
0 50 100
1 2 3 4 5
% Adsorption
Activated Carbon Type & IMC
IMC HCl/600˚C HCl/800˚C H2SO4/600˚C H2SO4/800˚C
0 50 100 150
1 2 3 4 5
% Adsorption
Activsted Carbon & IMC
IMC HCl/600˚C HCl/800˚C H2SO4/600˚C H2SO4/800˚C
0 50 100
1 2 3 4 5
% Adsorption
Activated Carbon Type & IMC
IMC HCl/600˚C HCl/800˚C H2SO4/600˚C H2SO4/800˚C
192
The AC carbonised at 800oC had a better percentage of adsorption except for those activated with H3PO4, but they all generally had a low percentage of adsorption and are not suitable for the removal of Ni from industrial effluents or liquid wastes (Table 4.135 and Figure 4.143).
Figure 4.144: Percentage Adsorption of Pb by SSAC
In the adsorption of Pb by SSAC, the AC carbonized at 600oC had a better percentage adsorption irrespective of the activating agent used though they all had low percentage of adsorption. This showed that it is not viable for use in the removal of Pb from waste (Table 4.136 and Figure 4.144).
Figure 4.145: Percentage Adsorption of Cd by SSAC
The adsorption of Cd by SSAC carbonized at both temperature values and activated with different reagents/acids was very low in all, though those carbonized at 600oC had a better percentage adsorption in most. Based on the aforesaid reason, they are not suitable to be used in the removal of Cd from liquid industrial effluents (Table 4.137, Figure 4.145).
0 20 40 60 80
1 2 3 4 5
% Adsorption
Activated Carbon Type & IMC
IMC HCl/600˚C HCl/800˚C H2SO4/600˚C H2SO4/800˚C H3PO4/600˚C
0 20 40 60
1 2 3 4 5
% Adsorption
Activated Carbon Type & IMC
IMC HCl/600˚C HCl/800˚C H2SO4/600˚C H2SO4/800˚C
193
Figure 4.146: Percentage Adsorption of Mn by SSAC
The percentage adsorptions of Mn by SSAC were generally low though those carbonized at 600oC had a better adsorption especially those activated with H3PO4
and H2SO4. Therefore, it is not recommended for use in the treatment of liquid industrial effluents contaminated with metals (Table 4.139).