{"title":"Polymeric resins containing modified starch as environmentally friendly adsorbents for dyes and metal ions removal from wastewater.","authors":"Anna Wołowicz, Monika Wawrzkiewicz, Beata Podkościelna, Bogdan Tarasiuk, Jadranka Blazhevska Gilev, Olena Sevastyanova","doi":"10.3389/fchem.2024.1496901","DOIUrl":null,"url":null,"abstract":"<p><p>Effective removal of organic and inorganic impurities by adsorption technique requires the preparation of new materials characterized by low production costs, significant sorption capacity, and reduced toxicity, derived from natural and renewable sources. To address these challenges, new adsorbents have been developed in the form of polymer microspheres based on ethylene glycol dimethacrylate (EGDMA) and vinyl acetate (VA) (EGDMA/VA) containing starch (St) modified with boric acid (B) and dodecyl-S-thiuronium dodecylthioacetate (DiTDTA) for the removal of dyes: C.I. Basic Blue 3 (BB3) and C.I. Acid Green 16 (AG16) and heavy metal ions (M(II)): Cu(II), Ni(II), and Zn(II) from water and wastewater. The adsorbents were characterized by ATR/FT-IR, DSC, SEM, BET, EDS, and pH<sub>PZC</sub> methods. These analyses demonstrated the successful modification of microspheres and the increased thermal resistance resulting from the addition of the modified starch. The point of zero charge for EGDMA/VA was 7.75, and this value decreased with the addition of modified starch (pH<sub>PZC</sub> = 6.62 for EGDMA/VA-St/B and pH<sub>PZC</sub> = 5.42 for EGDMA/VA-St/DiTDTA). The largest specific surface areas (S<sub>BET</sub>) were observed for the EGDMA/VA microspheres (207 m<sup>2</sup>/g), and S<sub>BET</sub> value slightly decreases with the modified starch addition (184 and 169 m<sup>2</sup>/g) as a consquence of the pores stopping by the big starch molecules. The total pore volumes (V<sub>tot</sub>) were found to be in the range from 0.227 to 0.233 cm<sup>3</sup>/g. These materials can be classified as mesoporous, with an average pore diameter (W) of approximately 55 Å (5.35-6.10 nm). The SEM and EDS analyses indicated that the EGDMA/VA microspheres are globular in shape with well-defined edges and contain 73.06% of carbon and 26.94% of oxygen. The microspheres containing modified starch exhibited a loss of smoothness with more irregular shape. The adsorption efficiency of dyes and heavy metal ions depends on the phases contact time, initial adsorbate concentration and the presence of competing electrolytes and surfactants. The equilibrium data were better fitted by the Freundlich isotherm model than by the Langmuir, Temkin, and Dubinin-Radushkevich models. The highest experimental adsorption capacities were observed for the BB3 dye which were equal to 193 mg/g, 190 mg/g, and 194 mg/g for EGDMA/VA, EGDMA/VA-St/B, EGDMA/VA-St/DiTDTA, respectively. The dyes and heavy metal ions were removed very rapidly and the time required to reach system equilibrium was below 20 min for M(II), 40 min for BB3, and 120 min for AG16. 50% v/v methanol and its mixture with 1 M HCl and NaCl for dyes and 1 M HCl for M(II) desorbed these impurities efficiently.</p>","PeriodicalId":12421,"journal":{"name":"Frontiers in Chemistry","volume":"12 ","pages":"1496901"},"PeriodicalIF":3.8000,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11557332/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Frontiers in Chemistry","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.3389/fchem.2024.1496901","RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2024/1/1 0:00:00","PubModel":"eCollection","JCR":"Q2","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
Effective removal of organic and inorganic impurities by adsorption technique requires the preparation of new materials characterized by low production costs, significant sorption capacity, and reduced toxicity, derived from natural and renewable sources. To address these challenges, new adsorbents have been developed in the form of polymer microspheres based on ethylene glycol dimethacrylate (EGDMA) and vinyl acetate (VA) (EGDMA/VA) containing starch (St) modified with boric acid (B) and dodecyl-S-thiuronium dodecylthioacetate (DiTDTA) for the removal of dyes: C.I. Basic Blue 3 (BB3) and C.I. Acid Green 16 (AG16) and heavy metal ions (M(II)): Cu(II), Ni(II), and Zn(II) from water and wastewater. The adsorbents were characterized by ATR/FT-IR, DSC, SEM, BET, EDS, and pHPZC methods. These analyses demonstrated the successful modification of microspheres and the increased thermal resistance resulting from the addition of the modified starch. The point of zero charge for EGDMA/VA was 7.75, and this value decreased with the addition of modified starch (pHPZC = 6.62 for EGDMA/VA-St/B and pHPZC = 5.42 for EGDMA/VA-St/DiTDTA). The largest specific surface areas (SBET) were observed for the EGDMA/VA microspheres (207 m2/g), and SBET value slightly decreases with the modified starch addition (184 and 169 m2/g) as a consquence of the pores stopping by the big starch molecules. The total pore volumes (Vtot) were found to be in the range from 0.227 to 0.233 cm3/g. These materials can be classified as mesoporous, with an average pore diameter (W) of approximately 55 Å (5.35-6.10 nm). The SEM and EDS analyses indicated that the EGDMA/VA microspheres are globular in shape with well-defined edges and contain 73.06% of carbon and 26.94% of oxygen. The microspheres containing modified starch exhibited a loss of smoothness with more irregular shape. The adsorption efficiency of dyes and heavy metal ions depends on the phases contact time, initial adsorbate concentration and the presence of competing electrolytes and surfactants. The equilibrium data were better fitted by the Freundlich isotherm model than by the Langmuir, Temkin, and Dubinin-Radushkevich models. The highest experimental adsorption capacities were observed for the BB3 dye which were equal to 193 mg/g, 190 mg/g, and 194 mg/g for EGDMA/VA, EGDMA/VA-St/B, EGDMA/VA-St/DiTDTA, respectively. The dyes and heavy metal ions were removed very rapidly and the time required to reach system equilibrium was below 20 min for M(II), 40 min for BB3, and 120 min for AG16. 50% v/v methanol and its mixture with 1 M HCl and NaCl for dyes and 1 M HCl for M(II) desorbed these impurities efficiently.
期刊介绍：
Frontiers in Chemistry is a high visiblity and quality journal, publishing rigorously peer-reviewed research across the chemical sciences. Field Chief Editor Steve Suib at the University of Connecticut is supported by an outstanding Editorial Board of international researchers. This multidisciplinary open-access journal is at the forefront of disseminating and communicating scientific knowledge and impactful discoveries to academics, industry leaders and the public worldwide.
Chemistry is a branch of science that is linked to all other main fields of research. The omnipresence of Chemistry is apparent in our everyday lives from the electronic devices that we all use to communicate, to foods we eat, to our health and well-being, to the different forms of energy that we use. While there are many subtopics and specialties of Chemistry, the fundamental link in all these areas is how atoms, ions, and molecules come together and come apart in what some have come to call the “dance of life”.
All specialty sections of Frontiers in Chemistry are open-access with the goal of publishing outstanding research publications, review articles, commentaries, and ideas about various aspects of Chemistry. The past forms of publication often have specific subdisciplines, most commonly of analytical, inorganic, organic and physical chemistries, but these days those lines and boxes are quite blurry and the silos of those disciplines appear to be eroding. Chemistry is important to both fundamental and applied areas of research and manufacturing, and indeed the outlines of academic versus industrial research are also often artificial. Collaborative research across all specialty areas of Chemistry is highly encouraged and supported as we move forward. These are exciting times and the field of Chemistry is an important and significant contributor to our collective knowledge.
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