Effect of microstructure and surface chemistry in liquid-phase adsorptive nicotine by almond-shell-based activated carbon

Abstract

The effect of microstructure and surface chemistry on nicotine adsorption capacity of almond-shell-based activated carbon was studied. Almond-shell-based activated carbon was reactivated or modified with steam, ZnCl 2 and NaHSO 4 separately. The surface area and pore structure parameters of activated carbon were determined from the adsorption-desorption isotherm of nitrogen at 77 K. Boehm titration and FTIR were explored to determine the surface oxygen groups. The results revealed that nicotine adsorption from solution on carbons depend on the micropores and phenolic groups. A strong correlation between the amounts of adsorbed nicotine and the phenolic groups was observed, whereas the higher amounts of carboxylic groups decrease the nicotine adsorption capacity on activated carbons. Nicotine which appears in mainstream cigarette smoke is a high-toxic agent in large quantity [1,2]. However, cigarette production generates large quantity of waste water with nicotine, which can easily pollute groundwater and affect human health. Some studies were performed with solid adsorbents to determine the adsorption capacity [3,4] with activated carbon as a reference adsorbent, but the application of modified activated carbon (changes of microstructure and surface oxygen groups) into adsorption of nicotine from aqueous solution has not been systematically investigated and reported. Our previous work shows that micropores and the surface chemistry of activated carbons play important roles during adsorption [5], and in this study, the aim is to determine which oxygen surface group plays a decisive role. Reactivation with steam and ZnCl 2 were employed for changing the microstructure and surface chemistry of almond-shell-based activated carbon, and a new chemical modification method was also used for changing the surface chemistry. NaHSO 4 solution is a good oxidation agent because its acidity is weaker than HNO 3 and could not destroy the microstructure of activated carbon. Moreover, Na + can be adsorbed onto the surface of activated carbon and create some micropores during the heat process due to the escape of Na atom. In the present work, we focus on examining the effects of microstructure and the type of surface oxygen groups on the adsorption performance.

Effect of oxidative modification of activated carbon for the adsorption behavior of nicotine

“…34 J mol K À1 . This may be due to increased 251 adsorption of hydrone on increased concentration of acidic 252 functional groups, especially carboxyl groups which can efficiently 253 combine with hydrone to form an hydration layer [17].…”

“…The processing of 14 tobacco for manufacture of cigarettes results in approximately 33% 15 of the tobacco being wasted. However, in recent years there have 16 been technological developments enabling utilisation of this 17 tobacco waste to produce tobacco slice. As for the process of 18 papermaking, large amounts of water are required to produce 19 tobacco slice.…”

“…It is also observed 136 that the pH pzc decreased from 6.3 for AC to 4.8 for MAC, most likely 137 due to this increase in concentration of acidic functional groups. In 138 contrast the oxidation process has little effect on physical 139 characteristics (Table 2) with the porous structure of AC and 140 MAC being nearly the same [17]. and that there are no interactions between the adsorbed 148 molecules.…”

“…Steric hindrance of nicotine can be ignored due to its 282 relatively small chemical structure. Both these factors promote the 283 formation of an electron donor-electron acceptor species 284 [17,27,28]. In addition, p-p interactions also promote the 285 adsorption of nicotine on AC and MAC [29].…”

Adsorption and desorption of the flavonoids on activated carbon impregnated with different metal ions

“…Thus, the functional groups and surface chemical characteristics determine the adsorption properties of AC [7]. The surface chemical properties of AC can be modi ed by oxidation, reduction and loading metal ion [8,9]. Metal ion modi cation for AC is a simple and economical method, the modi cation method can signi cantly improve the adsorption performance of AC [10].…”