Removal of Carbamazepine Onto Modified Zeolitic Tuff In
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water Article Removal of Carbamazepine onto Modified Zeolitic Tuff in Different Water Matrices: Batch and Continuous Flow Experiments Othman A. Al-Mashaqbeh 1,* , Diya A. Alsafadi 2, Layal Z. Alsalhi 1, Shannon L. Bartelt-Hunt 3 and Daniel D. Snow 4 1 Emerging Pollutants Research Unit, Royal Scientific Society, Amman 11941, Jordan; [email protected] 2 Biocatalysis and Biosynthesis Research Unit, Royal Scientific Society, Amman 11941, Jordan; [email protected] 3 College of Engineering, University of Nebraska–Lincoln, Omaha, NE 68583, USA; [email protected] 4 Water Sciences Laboratory, University of Nebraska, Lincoln, NE 68583, USA; [email protected] * Correspondence: [email protected] Abstract: Carbamazepine (CBZ) is the most frequently detected pharmaceutical residues in aquatic environments effluent by wastewater treatment plants. Batch and column experiments were con- ducted to evaluate the removal of CBZ from ultra-pure water and wastewater treatment plant (WWTP) effluent using raw zeolitic tuff (RZT) and surfactant modified zeolite (SMZ). Point zero net charge (pHpzc), X-ray diffraction (XRD), X-ray fluorescence (XRF), and Fourier Transform Infrared (FTIR) were investigated for adsorbents to evaluate the physiochemical changes resulted from the modification process using Hexadecyltrimethylammonium bromide (HDTMA-Br). XRD and FTIR Citation: Al-Mashaqbeh, O.A.; showed that the surfactant modification of RZT has created an amorphous surface with new alkyl Alsafadi, D.A.; Alsalhi, L.Z.; groups on the surface. The pHpzc was determined to be approximately 7.9 for RZT and SMZ. The Bartelt-Hunt, S.L.; Snow, D.D. results indicated that the CBZ uptake by SMZ is higher than RZT in all sorption tests (>8 fold). Batch Removal of Carbamazepine onto Modified Zeolitic Tuff in Different results showed that the sorption capacity of RZT and SMZ in WWTP effluent (0.029 and 0.25 mg/g) Water Matrices: Batch and is higher than RZT and SMZ (0.018 and 0.14 mg/g) in ultrapure water (1.6–1.8 fold). Batch tests Continuous Flow Experiments. Water showed that the equilibrium time of CBZ removal in the WWTP matrix (47 h) is much longer than 2021, 13, 1084. https://doi.org/ CBZ removal in ultrapure water. The sorption capacity of RZT & SMZ in WWTP effluent (0.03, 10.3390/w13081084 0.33 mg/g) is higher than RZT and SMZ (0.02 and 0.17 mg/g) in ultrapure water (1.5–2 fold) using column test. This study has clearly demonstrated that the performance of RZT and SMZ is more Academic Editor: Juan Carlos efficient for the removal of CBZ from realistic wastewater than ultrapure water. It is evident that the Leyva Diaz surfactant modification of RZT has enhanced the CBZ removal in both matrices. Received: 12 March 2021 Keywords: carbamazepine; matrix effect; sorption; surfactant-modification; zeolitic tuff Accepted: 5 April 2021 Published: 15 April 2021 Publisher’s Note: MDPI stays neutral 1. Introduction with regard to jurisdictional claims in published maps and institutional affil- Emerging pollutants such as pharmaceuticals and personal care products (PPCPs) iations. have been detected in municipal raw wastewater entering treatment plants (influent and effluent) ranging from sub-ng/L to µg/L levels. Among these PPCPs, carbamazepine (CBZ) is the most frequently detected pharmaceutical residue in aquatic environments [1–6]. CBZ is one of the most common psychoactive drugs used for treating many human diseases such as epileptic seizures, bipolar depression, and mania [7]. CBZ has high Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. stability, low adsorption capacity, therefore, it is poorly removed from wastewater treatment This article is an open access article systems. Thus, CBZ is currently used as a marker to evaluate the contamination of water distributed under the terms and bodies from PPCPs [8]. Many studies have detected CBZ in raw sewage (6.3 µg/L), in conditions of the Creative Commons wastewater treatment plants (17.3–22 µg/L), in river system (1.283 µg/L), and drinking Attribution (CC BY) license (https:// water (0.25 µg/L) [8,9]. Exposure to CBZ through drinking water may trigger autism creativecommons.org/licenses/by/ spectrum disorders during pregnancy [4]. Consequently, the removal of CBZ from the 4.0/). aqua ecosystem is recently considered a priority for many researchers. Water 2021, 13, 1084. https://doi.org/10.3390/w13081084 https://www.mdpi.com/journal/water Water 2021, 13, 1084 2 of 13 Adsorption is widely employed to remove emerging pollutants in wastewater treat- ment. It is the most efficient method in terms of simplicity, the cost of design and operation, and insensitivity of toxic substances [10,11]. Several adsorbents have been developed and tested to remove CBZ from wastewater matrices (i.e., zeolite) [12,13]. Natural zeolite has potential as a sorbent in multiple applications for water treatment and purification processes due to its physico-chemical characteristics, low cost, and widespread availabil- ity [14]. It includes minerals such as clinoptilolite, mordenite, phillipsite, and chabazite which can be utilized to sorb a variety of organic and inorganic compounds [14]. How- ever, the direct use of zeolite is often limited due to its low affinity for organic pollutants resulted from the net negative surface charge and hydrophilic surface properties [15,16]. Therefore, cost-effective surface modifications are needed to improve the sorbent capacity of zeolite materials. Studies found that zeolite can be modified with different cationic sur- factants (i.e., Hexadecyltrimethylammonium bromide-HDTMA-Br) creating a hydrophobic surface that enhances the organic sorption capacity from wastewater under different ex- perimental conditions [17–21]. Previous studies have shown that SMZ has a promising removal toward PPCPs in many applications [20,22,23]. For example, natural and modified zeolite by HDTMA-Br (SMZ) has shown significant sorption of diclofenac under differ- ent conditions [22]. While CBZ removal by SMZ has been studied using spiked CBZ in ultrapure water and/or synthetic wastewater, there is little work on the CBZ removal from realistic wastewater matrix [23]. The presence of dissolved organic matter (DOM) in secondary treated wastewater is recognized as the main factor limiting the adsorption of organic micropollutants onto activated carbon and its impact on the organic microp- ollutants adsorption is still unclear [23–27]. Therefore, this knowledge is needed for the design and optimization of using SMZ in the removal of PPCPs from realistic wastewater treatment systems. This work aims to evaluate the capacity and performance of RZT and surfactant modified zeolite by HDTMA-Br in the removal of CBZ compound from ultra-pure water and realistic wastewater (effluent). The sorption performance was further investigated under dynamic conditions using column studies under the same matrices. Furthermore, the point of zero charge, X-ray diffraction, X-ray fluorescence, and the Fourier transform infrared were performed to RZT and SMZ to understand the CBZ uptake mechanism. 2. Materials and Methods 2.1. Chemicals Analytical-grade of carbamazepine (CBZ) and Hexadecyltrimethylammonium Bro- mide (HDTMA-Br) (Sigma-Aldrich Chemical Company, St. Louis, MO, USA, 99%) were used. Influent solutions comprised ~10 mg/L of CBZ while the HDTMA-Br solution was ~48 g/L. The physical properties of CBZ are shown in Table1. Table 1. Classification and physical and chemical properties of carbamazepine. Water Molecular Compound Chemical Structure Drug Designation pKa Log Kow Solubilitymg/L Weightg/mol Carbamazepine Anticonvulsant 13.9 2.45 17.7 236.3 2.2. Zeolitic Tuff Preparation and Characterization Raw zeolitic tuff was collected by the Jordanian Scientific Company for Technological Development (TechDev Co., Amman, Jordan) from the Al-Safawi area/Al-Mafraq located north-east of Jordan. These samples are referred to as raw zeolitic tuff (RZT). RZT was subjected to crushing and sieving, one size was selected for further investigation. The selected size was between 2.36 mm < selected size < 4.75 mm. The selected RZT was washed with ultrapure water (Milli-Q Ultrapure, MilliporeSigma, Molsheim, France) water Water 2021, 13, 1084 3 of 13 over sieve no.12 to clean it from the fine particles, then it was soaked in ultrapure water for three days. The washed RZT was manually separated from grit limestone and the percentage of removed limestone was ~4.1%. RZT was then dried at 60 ◦C for three days and stored for further use. 2.2.1. Surfactant Chemical Modification Modification of the RZT surface was performed in this study using HDTMA-Br at a concentration equal to 200% of the external cation exchange capacity (ECEC) of the zeolite. The experimental ECEC value (0.144 mEq/g) was evaluated using the method suggested by de Gennaro et al., 2014 [18]. The solution equivalent was prepared by mixing 48 g of HDTMA-Br and 1000 mL ultrapure water using a magnetic stirrer at 500 rpm at 50 ◦C (temp. of solution) until a clear solution was reached. Then, 500 g of RZT was placed in the HDTMA-Br solution and mixed using an orbital shaker for 6-h at 120 rpm and 50 ◦C. The pH and EC of solution before and after were 5.674 and 2.65 mS/cm, and 8.173 and 4.9 mS/cm, respectively. After 6-h the modified RZT was washed with ultrapure water to remove the unnecessary surfactant and then dried in an oven at 35 ◦C for 24-h. Modified raw zeolitic tuff was referred to as surfactant modified zeolite (SMZ). 2.2.2. Point of Zero Net Charge (pzc) pHpzc of RZT and SMZ were determined according to the method described by Kragovi´cet al., 2019 [28]. 0.1 g of crushed RZT and SMZ were transferred to six beakers (50 mL) containing 30 mL of 0.1 mol /L KNO3 prepared in ultrapure water with adjusted pH values from 2 to 12 (pH = 2, 4, 6, 8, 10, and 12).