Abstract
t-Butyl hydroperoxide-initiated cycloterpolymerization of diallylaminoaspartic acid hydrochloride [(CH2 Created by potrace 1.16, written by Peter Selinger 2001-2019 ]]> CHCH2)2NH+CH(CO2H)CH2CO2H Cl−] (I), maleic acid (HO2CHCHCO2H) (II) and cross-linker tetraallylhexane-1,6-diamine dihydrochloride [(CH2CHCH2)2NH+(CH2)6NH+ (CH2CHCH2)2 2Cl−] (III) afforded a new pH-responsive resin (IV), loaded with four CO2H and a chelating motif of NH+⋯CO2− in each repeating unit. The removal of cationic methylene blue (MB) (3000 ppm) at pH 7.25 and Pb(ii) (200 ppm) at pH 6 by IV at 298, 313, and 328 K followed second-order kinetics with Ea of 33.4 and 40.7 kJ mol−1, respectively. Both MB and Pb(ii) were removed fast, accounting for 97.7% removal of MB within 15 min at 313 K and 94% of Pb(ii) removal within 1 min. The super-adsorbent resin gave respective qmax values of 2609 mg g−1 and 873 mg g−1 for MB and Pb(ii). IV was also found to trap anionic dyes; it removed 91% Eriochrome Black T (EBT) from its 50 ppm solutions at pH 2. The resin was found to be effective in reducing priority metal contaminants (like Cr, Hg, Pb) in industrial wastewater to sub-ppb levels. The synthesis of the recyclable resin can be easily scaled up from inexpensive starting materials. The resin has been found to be better than many recently reported sorbents.
Highlights
Industrial effluents containing dyes damage the aquatic environment
The % mol ratio of monomers 5/6/4 incorporated into the resin was approximated to be 37.4 : 54.2 : 8.4, same as the feed ratio; this is expected at such a high conversion
Neither diallyamine salts nor maleic acid can undergo homopolymerization; the polymerization invariably leads to the formation of alternate addition of diallylamine salt and maleic acid.[18]
Summary
Industrial effluents containing dyes damage the aquatic environment. The remediation of dye-contaminated wastewater is highly signi cant for the protection of the environmental ecology. The textile industry uses methylene blue (MB), which is discharged into the environment via the effluents of textile, paper, and printing industries,[1] thereby causing various ecological problems.[2] Commercial annual production of dyes is z7 Â 105 tons, a considerable fraction of which is discharged directly in aqueous effluent.[3] The dyes discharged into river streams cause enormous harm to aquatic life[4] by reducing light penetration and photosynthesis.[5] In addition to being carcino- and muta-genic, most dyes are not biodegradable,[6] which makes bioremediation[7] an inefficient process.[8]
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