Agarose-Immobilized LTA Zeolite: a Novel Material to Use in an Improved Treatment Process of Mine-Impacted Water

Use of a Waste-Derived Linde Type-A Immobilized in Agarose for the Remediation of Water Impacted by Coal Acid Mine Drainage at Pilot Scale

“…In order to be used as an adsorbent, the LTA zeolite was washed three times with ultrapure water, vacuum filtered through a 0.45-µm cellulose acetate membrane, dried afterwards in an oven at 80 • C for 24 h, and then kept within a desiccator [33].…”

“…The preparation of the adsorbent material was previously studied and optimized [33]. Basically, the LTA zeolite immobilized in agarose gel was prepared from a suspension of LTA (8%, m/v) and agarose (1.5%, m/v) in ultrapure water heated at 90 ± 1 • C and stirred until suspension homogenization.…”

“…Basically, the LTA zeolite immobilized in agarose gel was prepared from a suspension of LTA (8%, m/v) and agarose (1.5%, m/v) in ultrapure water heated at 90 ± 1 • C and stirred until suspension homogenization. This homogeneous suspension was then cooled to 55 ± 1 • C, and the gel was molded by pouring 30 mL between two glass plates, which were previously heated (~60 • C) and separated with 0.92-mm spacers to delimit thickness of the formed film [33,37,38]. The produced films were then cut into slices (Figure 1a,b) and dried at room temperature for 72 h (Figure 1c,d).…”

“…The produced films were then cut into slices (Figure 1a,b) and dried at room temperature for 72 h (Figure 1c,d). In a previous study [33], AG-LTA was characterized, before and after sorption of metal ions, via scanning electron microscope (SEM), energy dispersive X-ray (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analyses (TGA). That study showed no alterations in the structure of LTA zeolite after immobilization.…”

“…The above-mentioned LTA properties have been demonstrated in a study by experiments aiming at the removal of metallic contaminants from a synthetic solution alike AMD-impacted water [24]. In our previous research, we discussed the LTA immobilization in agarose gel (AG), which was successfully applied in batch regime for removal of Fe 2+ , Mn 2+ , and Al 3+ ions from a synthetic solution and real samples of AMD-impacted water [33,34]. The goal was achieving zeolite stability under acidic conditions (characteristic of AMD-impacted water) as well as facilitate the removal of the ion-saturated adsorbent from the treated medium.…”