Abstract:The scientific impact of this work is the protection of the environment from hazardous pollutants using a column technique. Besides its higher stability at working pH and its time persisting, Ni-alginate has a higher ability to remove lead ions compared to the other prepared beads (Sr-alginate, Co-alginate, and Ca-alginate). Also, Ni-alginate possessed a higher removal percent, 93.3%, toward Pb2+ than the other ions, taking the sorption order of Pb2+ > Sr2+ > Co2+ > Cd2+ > Zn2+. Therefore, this stu… Show more
“…To investigate the industrial applicability of alginate materials for Pb adsorption, the best-performing adsorbent arising from batch experiments was compared to Amberlite using a packed bed ion-exchange system. Each adsorbent was packed separately into transparent cylindrical columns with a diameter of 1.2 cm and bed height of 3 cm in accordance with Sami et al ( 2022 ). A peristaltic pump with a flow meter was used to pump fresh feed into the top of the column as shown in Fig.…”
Section: Methodsmentioning
confidence: 99%
“…1 . The column was fed in a downward flow direction to withdraw any trapped air between the beads and control the rate of flooding in the column (Sami et al 2022 ). Fig.…”
Driven by climate change and human activity, Sargassum blooming rates have intensified, producing copious amount of the invasive, pelagic seaweed across the Caribbean and Latin America. Battery recycling and lead-smelter wastes have heavily polluted the environment and resulted in acute lead poisoning in children through widespread heavy metal contamination particular in East Trinidad. Our study details a comprehensive investigation into the use of Sargassum (S. natans), as a potential resource-circular feedstock for the synthesis of calcium alginate beads utilized in heavy metal adsorption, both in batch and column experiments. Here, ionic cross-linking of extracted sodium alginate with calcium chloride was utilized to create functional ion-exchange beads. Given the low quality of alginates extracted from Sargassum which produce poor morphological beads, composite beads in conjunction with graphene oxide and acrylamide were used to improve fabrication. Stand-alone calcium alginate beads exhibited superior Pb2+ adsorption, with a capacity of 213 mg g−1 at 20 °C and pH 3.5, surpassing composite and commercial resins. Additives like acrylamide and graphene oxide in composite alginate resins led to a 21–40% decrease in Pb2+ adsorption due to reduced active sites. Column operations confirmed Alginate systems’ practicality, with 20–24% longer operating times, 15 times lower adsorbent mass on scale-up and 206% smaller column diameters compared to commercial counterparts. Ultimately, this study advocates for Sargassum-based Alginate ion-exchange beads as a bio-based alternative in Trinidad and developing nations for dealing with heavy metal ion waste, offering superior heavy metal adsorption performance and supporting resource circularity.
Graphical Abstract
“…To investigate the industrial applicability of alginate materials for Pb adsorption, the best-performing adsorbent arising from batch experiments was compared to Amberlite using a packed bed ion-exchange system. Each adsorbent was packed separately into transparent cylindrical columns with a diameter of 1.2 cm and bed height of 3 cm in accordance with Sami et al ( 2022 ). A peristaltic pump with a flow meter was used to pump fresh feed into the top of the column as shown in Fig.…”
Section: Methodsmentioning
confidence: 99%
“…1 . The column was fed in a downward flow direction to withdraw any trapped air between the beads and control the rate of flooding in the column (Sami et al 2022 ). Fig.…”
Driven by climate change and human activity, Sargassum blooming rates have intensified, producing copious amount of the invasive, pelagic seaweed across the Caribbean and Latin America. Battery recycling and lead-smelter wastes have heavily polluted the environment and resulted in acute lead poisoning in children through widespread heavy metal contamination particular in East Trinidad. Our study details a comprehensive investigation into the use of Sargassum (S. natans), as a potential resource-circular feedstock for the synthesis of calcium alginate beads utilized in heavy metal adsorption, both in batch and column experiments. Here, ionic cross-linking of extracted sodium alginate with calcium chloride was utilized to create functional ion-exchange beads. Given the low quality of alginates extracted from Sargassum which produce poor morphological beads, composite beads in conjunction with graphene oxide and acrylamide were used to improve fabrication. Stand-alone calcium alginate beads exhibited superior Pb2+ adsorption, with a capacity of 213 mg g−1 at 20 °C and pH 3.5, surpassing composite and commercial resins. Additives like acrylamide and graphene oxide in composite alginate resins led to a 21–40% decrease in Pb2+ adsorption due to reduced active sites. Column operations confirmed Alginate systems’ practicality, with 20–24% longer operating times, 15 times lower adsorbent mass on scale-up and 206% smaller column diameters compared to commercial counterparts. Ultimately, this study advocates for Sargassum-based Alginate ion-exchange beads as a bio-based alternative in Trinidad and developing nations for dealing with heavy metal ion waste, offering superior heavy metal adsorption performance and supporting resource circularity.
Graphical Abstract
“…12 Consequently, the hydrogel possesses strong separability, making it suitable for the adsorption and recovery of heavy metal ions from wastewater. Sami et al 13 investigated the adsorption of lead by different types of alginate hydrogel beads prepared using cross-linking agents and tested their efficiency in removing lead. Among the adsorbent materials tested, Ni 2+ -sodium alginate (SA) displayed the best adsorption capacity for lead, reaching 22.8 mg/g.…”
In this paper, a carbon dot hydrogel composite (CDs-Hy) capable of efficiently removing Pb(II) was prepared by hydrogen bonding self-assembly in combination with carbon dots and a hydrogel. CDs-Hy was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS), and the effect of the adsorption conditions on the adsorption efficiency of CDs-Hy was studied. The results of the study showed that the incorporation of carbon dots, on the one hand, significantly increased the adsorption capacity of the material. On the other hand, it can increase the stability of hydrogels in aqueous solution. The possible adsorption mechanisms were further verified as ion exchange and coordination. CDs-Hy is a novel adsorbent material capable of removing Pb 2+ efficiently, which can be reused several times with high stability.
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