Factorial experimental design applied to adsorption of cadmium on activated alumina

Abstract

The effective removal of heavy metals from industrial wastewater is a very important issue for many countries. This paper examines the removal of cadmium ions from aqueous solutions and industrial effluents by adsorption on activated alumina. The Brunauer–Emmett–Teller (BET) specific surface area, pore diameter and pore volume of the activated alumina were 156.7 m2/g, 58.4 Å and 0.23 cm3/g, respectively. Factorial experimental design was applied to evaluate the main effects and interactions among dose of activated alumina, initial cadmium concentration, pH of the solution and temperature. Analysis of variance, the F-test and the Student's t-test shows that dose of activated alumina, initial cadmium ion concentration and temperature are the most significant parameters affecting cadmium ion removal and pH is the least significant parameter. Under optimal conditions, cadmium removal from industrial effluent samples was >98%. Furthermore, desorption and regeneration studies were carried out in order to evaluate the cost-effectiveness of activated alumina.

Parametric Study of Methyl Orange Removal Using Metal–Organic Frameworks Based on Factorial Experimental Design Analysis

“…For pH initial less than pH PZC , the MOF's surface is more positively charged, which strengthens the electrostatic attraction to MO molecules that are usually in the negatively charged sulfonate form. Additionally, for pH initial greater than pH PZC , the surface of the MOF is more negatively charged, which leads to strong repulsion between the MOF's surface and MO molecules (both are negatively charged) [22,68]. In the cases of Fe-BTC and ZIF-8, the pH PZC was around 9 and 9.5, respectively.…”

“…Recently, metal-organic frameworks (MOFs) came into view as promising adsorbents. MOFs are porous solid materials comprised of metal clusters (blocks) connected by organic ligands via coordination bonds and have exceptional adsorbent properties that make them superior to other conventional porous solids [22]. Haque et al (2010) were the first group to report the adsorptive removal of dyes using MOFs, where they employed chromium-benzene dicarboxylates MOFs (Cr-BDCs) for methyl orange (MO) adsorption [22].…”

“…MOFs are porous solid materials comprised of metal clusters (blocks) connected by organic ligands via coordination bonds and have exceptional adsorbent properties that make them superior to other conventional porous solids [22]. Haque et al (2010) were the first group to report the adsorptive removal of dyes using MOFs, where they employed chromium-benzene dicarboxylates MOFs (Cr-BDCs) for methyl orange (MO) adsorption [22]. Since then, several investigators have reported their findings on the removal of different dyes using various lab-synthesized MOFs as adsorbents [14][15][16][17][18][19][20][21][22][23][24][25][26]-for example, iron 1,3,5-benzenetricarboxylate (Fe-BTC) MOF, has been used in the liquid-phase separation of various molecules/compounds (organic and inorganic) [27,28].…”

“…Haque et al (2010) were the first group to report the adsorptive removal of dyes using MOFs, where they employed chromium-benzene dicarboxylates MOFs (Cr-BDCs) for methyl orange (MO) adsorption [22]. Since then, several investigators have reported their findings on the removal of different dyes using various lab-synthesized MOFs as adsorbents [14][15][16][17][18][19][20][21][22][23][24][25][26]-for example, iron 1,3,5-benzenetricarboxylate (Fe-BTC) MOF, has been used in the liquid-phase separation of various molecules/compounds (organic and inorganic) [27,28]. Similarly, copper benzene-1,3,5-tricarboxylate (Cu-BTC) is a widely investigated MOF in different environmental applications, such as gas storage and adsorptive separation [29,30], and was used for methylene blue adsorption from water [31].…”

Iron-Loaded Pomegranate Peel as a Bio-Adsorbent for Phosphate Removal

“…Figure 8 plots the interactions of the studied parameters. If the interaction lines are not parallel, this implies that the interaction has a strong effect, whereas parallel interaction lines indicate a weak effect [62]. The most important interaction for PO 4 3− removal by IL-PP appears to be pH*adsorbent dose, which is followed by adsorbent dose*temperature.…”