Magnetic Hierarchically Macroporous Emulsion-Templated Poly(acrylic acid)–Iron Oxide Nanocomposite Beads for Water Remediation

Abstract

Tainting of waterbodies with noxious industrial waste is the gravest environmental concern of the day that continues to wreak inevitable havoc on human health. To cleanup these hard-to-remove life-threatening water contaminants, we have prepared hierarchically porous poly(acrylic acid) beads by emulsion templating. These emulsion-templated macroporous polymer beads not only mediate the synthesis of Fe 3 O 4 nanoparticles inside their porous network using a coprecipitation approach but, in turn, create diverse anchoring sites to immobilize an additional poly(acrylic acid) active layer onto the nanocomposite beads. These post-synthetically modified nanocomposite beads with macropores and abundant acrylic acid moieties offer the ready mass transfer and fair advantage of relatively higher overall negative charge to efficiently adsorb lead [Pb(II)] and crystal violet with impressive performanceeven superior to many of the materials explored in this regard so far. Furthermore, the strong entanglement of nanoparticles in the porous polymeric scaffolds tackles the curb of trade-off between all-round effective remediation and secondary pollution and the millimeter size eases their processing and recovery during the adsorption tests, thereby making these materials practically worthwhile.

Fundamentals and Design‐Led Synthesis of Emulsion‐Templated Porous Materials for Environmental Applications

“…[20,100] Nano/microscale materials offer impressive performance though; their practical applications are limited by the drawbacks associated with their processing and recovery, whereas the millimeter size eases the handling and subsequent separation of macrosized materials during the application tests, thereby making such materials practically worthwhile. [98,[101][102][103] The precise control over all these synthetic parameters is tricky and can be successfully achieved by trial-and-error experiments and a lot of development is still in process for further advancement. In this connection, the emulsion templating produces materials of high porosities (64-97%) with a wide pore size range (100 nm-2 mm).…”

“…[23,25,174] The strong entanglement of inorganic particles into the millimeter size porous organic polymer scaffolds overcomes the problem of trade-off between effective remediation and secondary contamination and eases their complicated processability during and after the application tests, thereby making such materials practically valuable especially to develop decentralized water treatment systems. [103] The following subsections provide a detailed discussion on the preparation methods of the emulsion-templated porous hybrid and composite materials.…”

“…These inorganic pollutants lead to severe health problems including kidney infection, renal abnormalities, renal damage, lung infection, heart attacks, liver infection, mental retardation, edema to the immune system, asthma, anemia, numerous types of cancer, allergic reactions, hypertension, DNA damaging, and reduction in fertility in animals and human. [103,[267][268][269] Pb 2+ /Cd 2+ /Cu 2+ : Pb, Cd, and Cu are typically considered to be the conventional water contaminants. Pb is one of the most toxic heavy metals and permissible to be 0.01 and 0.015 mg L −1 in drinking water according to the World Health Organization (WHO) and US Environmental Protection Agency (USEPA).…”

“…[ 20 , 100 ] Nano/microscale materials offer impressive performance though; their practical applications are limited by the drawbacks associated with their processing and recovery, whereas the millimeter size eases the handling and subsequent separation of macrosized materials during the application tests, thereby making such materials practically worthwhile. [ 98 , 101 , 102 , 103 ]…”

Recent advances in separation applications of polymerized high internal phase emulsions

“…Therefore, adsorption method is a preferred separation method for metal ions because of its simple, rapid, and high efficiency. PolyHIPEs with oxygen‐, nitrogen‐, and sulfur‐containing functional groups, or grafted with EDTA, aniline, pyridine, crown ether, or other organic compounds, have been successfully demonstrated effective in the adsorption separation of various metal ions, including Ag + [36], Cs + [129, 130], Li + [131–135], Rb + [130, 135], Cd 2+ [36, 136–138], Cu 2+ [36, 75,103, 138–143], Hg 2+ [144], Ni 2+ [98], Pb 2+ [72, 136, 142, 145], Sr 2+ [130, 135], Zn 2+ [143], Cr(IV) [146, 147], plutonium ions [148, 149], and rare‐earth metal ions (Ce 3+ , La 3+ ) [150] through direct adsorption or ion‐exchange process.…”