A nanocomposite based on polyaniline, nickel and manganese oxides for dye removal from aqueous solutions

Hollow Polyaniline Microsphere/MnO2/Fe3O4 Nanocomposites in Adsorptive Removal of Toxic Dyes from Contaminated Water

“…The absence of any significant changes in the binding energy peaks conforming to Fe 2p 3/2 and Fe 2p 1/2 in Figure f before and after dye adsorption indicated the stability of Fe 3 O 4 in the PNHM/MnO 2 /Fe 3 O 4 adsorbent . Alternatively, the role of an interface through the hydrogen bonding and π–π interaction between dye molecules and benzene rings of PANI present in PNHM cannot be ruled out in the adsorption process. , Figure demonstrates the schematic representation of MG and CR dye adsorption mechanism on PNHM/MnO 2 /Fe 3 O 4 at pH ∼6.75.…”

“…The removal of organic and inorganic pollutants, for instance, dyes, heavy metals/metalloids, fluoride, iron, nitrate, humic substances, phenolic compounds, pesticides, dioxins, petroleum surfactants, pharmaceuticals, and personal care products from the aqueous media have gained significant attention due to the continuous depletion of freshwater resources. − Among these, dyes are released relatively in large amounts due to their vast area of applications in different industries, including foodstuff, varnish, paints, paper and printing, plastic, leather, textile, cosmetics, and pharmaceuticals. − According to the available literature, over 700 000 metric tonnes per annum of dyes are generated globally from different sources. , Such direct discharge of untreated or partially treated dye-containing effluents leads to detrimental impacts on the ecosystem’s health and sustainability. Consequently, the accumulation of these pollutants can affect aquatic lives by reducing the photosynthesis efficiency and contributing severe toxic, carcinogenic, and mutagenic effects on human health and animals. , In addition, some dyes (e.g., neutral red) undergo natural degradation and produce harmful byproducts …”

“…), and hybrid processes (Fenton/chemical coagulation, UV/electro-Fenton, membrane/photocatalysis etc. ). − Among these, the adsorption process has gained considerable attention because of its simple operation, wide range of applications, cost-effectiveness, high removal capacity, high selectivity, recycling facilities, etc . Considering the factors mentioned above, the present work is focused on the adsorptive removal of cationic methyl green (MG) and anionic Congo red (CR), owing to their excessive use in industrial and biological sectors as well as their ecotoxicological effects. − Further, the performance of the adsorbent is determined based on the desired characteristics of an efficient adsorbent, including simple synthesis routes, nontoxicity, high adsorption capacity, and recycling ability .…”

“…Considering the factors mentioned above, the present work is focused on the adsorptive removal of cationic methyl green (MG) and anionic Congo red (CR), owing to their excessive use in industrial and biological sectors as well as their ecotoxicological effects. − Further, the performance of the adsorbent is determined based on the desired characteristics of an efficient adsorbent, including simple synthesis routes, nontoxicity, high adsorption capacity, and recycling ability . Therefore, various adsorbents such as activated carbon, carbon nanotubes, graphene oxides, natural clay materials, layered double hydroxides, metal-organic frameworks, metal oxides, conducting polymers, and their hybrids have been used as adsorbents for the removal of dyes from aqueous media. , Among these, conducting polymer-based adsorbents are of prime interest owing to their diverse physicochemical properties, low cost, and wide applications in various fields, including environmental remediation, electromagnetic shielding instruments, extraction, and electrochemical applications. ,, …”

“…Consequently, the accumulation of these pollutants can affect aquatic lives by reducing the photosynthesis efficiency and contributing severe toxic, carcinogenic, and mutagenic effects on human health and animals. 8,9 In addition, some dyes (e.g., neutral red) undergo natural degradation and produce harmful byproducts. 8 In view of this, it is essential to remove the toxic dyes from water bodies by treating them through various treatment techniques, for instance, physicochemical (electrocoagulation, ion-exchange, adsorption, membrane filtration, advanced oxidation processes, etc.…”