Novel Ti-Coordination Polydopamine Nanocomposite with a Combination of Adsorption, Reduction, and Ion Exchange for Rapid Cr(VI) Removal

Abstract

Adsorption is one of the most economical and effective technologies for the remediation of Cr­(VI) pollution. Due to the high toxicity and mobility of Cr­(VI), however, Cr­(VI)-laden adsorbents are still very toxic and dangerous solid pollutants after usage and require special attention. To tackle this issue, herein, we present a facile yet simple strategy to prepare a novel advanced adsorbent based on Ti-coordination polydopamine nanocomposites (TCPNs) for rapid Cr­(VI) adsorption, reduction, and ion exchange to achieve better Cr­(VI) detoxification and fixation. The TCPNs were synthesized by combining Ti and dopamine coordination with sequent self-polymerization of the resulting Ti–dopamine complexes under hydrothermal conditions. The as-prepared TCPNs were characterized with a combination of scanning electron microscopy (SEM) and energy-dispersive spectrometry (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Special efforts have been devoted to investigating the effect of solution pH, contact time, TCPN dosage, and initial Cr­(VI) concentration on the adsorption kinetics and isotherm of TCNPs to Cr­(VI). The adsorption results show that the developed TCPN adsorbent possesses a high Cr­(VI) adsorption capacity of 370 mg/g at a low Cr­(VI) concentration of 50 mg/L and can rapidly reduce the Cr­(VI) concentration from 10 mg/L to an extremely low level of smaller than 0.02 mg/L in 15 min. In addition, TCPNs have obviously high selectivity and preference to Cr­(VI) when compared to other coexisting competing ions. Finally, the mechanism studies reveal that TCPNs achieve this satisfactory Cr­(VI) detoxification and fixation through a combination of rapid adsorption, reduction, and ion exchange.

Engineering of Adhesion at Metal–Poly(lactic acid) Interfaces by Poly(dopamine): The Effect of the Annealing Temperature

“…The broad band located at ∼3300 cm –1 is associated with the ν­(N–H) and ν­(O–H) stretching vibrations originating from primary amines, water, and catechol groups. − The “shoulders” at ∼2950 and ∼1720 cm –1 correspond to the ν­(C–H) stretching of aliphatic carbons ,, and ν­(CO) vibrations of quinone groups, , respectively. The peak at ∼1585 cm –1 is assigned to the ν­(CC) stretching mode of the aromatic rings. , The peak at ∼1505 cm –1 has been previously attributed to the ν­(C–N) stretching − and ν­(N–H) scissoring , vibrations. Finally, the overlapping peaks between ∼1405 and ∼1060 cm –1 are assigned to ν­(C–O) ,, and ν­(C–N) vibrations.…”

“…The peak at ∼1585 cm –1 is assigned to the ν(C=C) stretching mode of the aromatic rings. 43 , 46 The peak at ∼1505 cm –1 has been previously attributed to the ν(C–N) stretching 47 − 49 and ν(N–H) scissoring 19 , 47 vibrations. Finally, the overlapping peaks between ∼1405 and ∼1060 cm –1 are assigned to ν(C–O) 46 , 50 , 51 and ν(C–N) 52 vibrations.…”

Naturally derived materials to enhance the membrane properties in (waste)water treatment applications - Mechanisms, scale-up challenges and economic considerations

“…The electrostatic interactions between the pollutants and adsorbent are highly dependent on their surface charges; hence, the solution pH and surface charges of membranes play key roles in their attractive or repulsive forces [43]. In addition, ion exchange is basically classified into cation exchange for the adsorption of positively charged ions and anion exchange for the removal of negatively charged ions in the medium [44]. Hbonding is another main adsorption mechanism based on the electrostatic attraction between a hydrogen atom covalently bonded to a very electronegative atom (i.e., O, N) [45].…”

Superstable Mineralization Coupled with Photocatalysis toward Cr(VI) Remediation Using Layered Double Hydroxide Material

“…Adsorption is considered an exceptionally effective strategy for eliminating Cr­(VI) for its ease of operation, high treatment efficiency, and large adsorption capacity. , In recent years, various adsorbent materials have been utilized to treat heavy metal pollution, including activated carbon, mineral materials, zeolites, etc. However, these materials often exhibit weak binding forces and low adsorption efficiencies, resulting in a potential second pollution, thus restricting their application in the industry.…”