Comparison of activated carbon prepared from olive stones by microwave and conventional heating for iron (II), lead (II), and copper (II) removal from synthetic wastewater

Abstract

Activated carbon with high surface area was prepared from olive stone by microwave heating (MHOS) for the removal of a group of heavy metals Fe 21 , Pb 21, and Cu 21 from synthetic wastewater. As a comparison, activated carbon was also prepared by conventional heating (CHOS) method. The effects of different reaction parameters, such as adsorbent dosage, contact time, stirring speed, and initial pH, on pollutant removal efficiency were determined. The microwave heating requires significantly lesser holding time as compared to conventional heating method to produce activated carbon of comparable quality, with higher yield. The BET surface area of carbon using microwave heating is noticeably higher than the conventional heating. Although the mesopore surface area of carbon is not vary significantly, the activation time and power consumption are considerably lower than the conventional heating rendering that the activation process via microwave is more economical than that via conventional heating. The adsorption capacity was found higher using microwave heating as compared with conventional heating. The adsorption equilibrium data were best represented by the Langmuir model and the adsorption capacity for Fe 21 , Pb 21 and Cu 21 were found to be 62.50, 23.47, and 22.73 mg=g for MHOS; while 57.47, 22.37, and 17.83 mg=g for CHOS, respectively at pH 5, 3 h contact time and 200 rpm shaking speed. Regeneration studies showed that MHOS and CHOS could be used several times by desorption with an HCl reagent. A pseudo second-order model sufficiently described the adsorption kinetics for both carbons, which indicates that the adsorption process was controlled by chemisorption. Both carbons can be used for the efficient removal of Fe 21 , Pb 21 , and Cu 21 (>99%) from contaminated wastewater.

Preparation of new polysulfone capsules containing Cyanex 272 and their properties for Co(II) removal from aqueous solution

“…Loading the capsules was carried out by using 25 mg/L Co(II) solution at experimental conditions: initial pH 8.0, capsule amount: 10 g/L, contact time: 120 min, shaking speed 200 rpm, temperature: 25 AE 1 C. According to the Cytec Co., which produces Cyanex 272 [22], after liquid-liquid extraction of Co(II) with organic solvent Kermac 470B containing 12% Cyanex 272 as extractant and 10% p-nonylphenol as modifier, HCl solution can be used to strip Co(II) from loading organic phase. Moreover, Alslaibi et al [53] indicated that HCl solutions with different concentrations are efficient metal desorption solutions. They reported [52] that desorption of Fe 2+ , Pb 2+ and Cu 2+ from activated carbon prepared from olive stones by using microwave and conventional heating was found to be more effective by using 0.1 M HCl solution.…”

“…Therefore, in our study, we used 0.1 M HCl solution for desorption of Co(II) from loaded Cyanex 272@PSF capsules. It was found that desorption of Co(II) by using 0.1 M HCl solution was effective, which can be attributed to that the H + from HCl easily displaces Co(II) ions bonded to the capsules during the desorption process [53]. After desorption, Cyanex 272@PSF capsules were washed with distilled water untill neutralization and dried at room temperature.…”

“…The sorption behavior of an adsorbent for a metal ion depends on a combined action of solution pH, electronegativity and ionic radius of metal ion [53,56,57]. Electronegativity of a metal ion indicates the tendency of the metal ion attraction to the negatively charged sites.…”

Simultaneous adsorption behavior of heavy metals onto microporous olive stones activated carbon: analysis of metal interactions

“…The use of agriculture byproducts such as coconut fruit (Anirudhan and Sreekumari 2011), nuts apricot (Tsibranska and Hristova 2010), beet pulp (Pehlivan et al 2008), stems of tea (Amarasinghe and Williams 2007), rice husk (Bakircioglu et al 2003;Wong et al 2003), pentandra hulls (Madhava-Raoa et al 2006)and olive stones-waste (Alslaibi et al 2015;Baccar et al 2009;Gharib and Ouederni 2005), which are inexpensive, abundantly available, and renewable materials, as precursor for activated carbon production, reduces adsorption processing costs (Bailey et al 1999). The adsorption process offers flexibility in design and operation and in many cases will produce high-quality treated effluent (Fu and Wang 2011;Cui et al 2016).…”

Application of apricot stone waste from fruit processing industry in environmental cleanup: copper biosorption study

“…Also the lignocellulose material can be used as adsorbent for the removal of pollutants from the wastewater either in its native form [2,3], treated form [4][5][6][7], or for production of active carbon [8,9]. Although there are several conventional treatments of wastewater, researchers are focused on the development of biotechnological solutions that are environmental friendly [10].…”