This review summarizes the characterization and quantification of interactions between dissolved organic matter (DOM) and estrogens as well as the effects of DOM on aquatic estrogen removal. DOM ...interacts with estrogens via binding or sorption mechanisms like π-π interaction and hydrogen bonding. The binding affinity is evaluated in terms of organic-carbon-normalized sorption coefficient (Log KOC) which varies with types and composition of DOM. DOM has been suggested to be a more efficient sorbent compared with other matrices, such as suspended particulate matter, sediment and soil; likely associated with its large surface area and concentrated carbon content. As a photosensitizer, DOM enhanced estrogen photodegradation when the concentration of DOM was below a threshold value, and when above, the acceleration effect was not observed. DOM played a dual role in affecting biodegradation of estrogens depending on the recalcitrance of the DOM and the nutrition status of the degraders. DOM also acted as an electron shuttle (redox mediator) mediating the degradation of estrogens. DOM hindered enzyme-catalyzed removal of estrogens while enhanced their transformation during the simultaneous photo-enzymatic process. Membrane rejection of estrogens was pronounced for hydrophobic DOM with high aromaticity and phenolic moiety content. Elimination of estrogens via photolysis, biodegradation, enzymolysis and membrane rejection in the presence of DOM is initiated by sorption, accentuating the role of DOM as a mediator in regulating aquatic estrogen removal.
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•Dissolved organic matter interacts with estrogens via binding or sorption.•Binding mechanisms include π-π electron donor-acceptor interaction and hydrogen bonding.•The interactions were primarily associated with dissolved organic carbon quality.•Methods to characterize and quantify binding or sorption affinity were summarized.•The regulatory effects of dissolved organic matter on estrogen elimination were discussed.
The UV/persulfate (PS) process is a promising water treatment technology, and it can not only effectively degrade contaminants of emerging concern, but also control formation of disinfection ...byproducts (DBPs). In this study, we investigated the potential and mechanisms of chloropicrin (i.e. trichloronitromethane, TCNM) formation during chlorination that followed UV/PS pretreatment in the presence of low concentrations of nitrite. We found that when nitrite was present in the UV/PS system, unexpected high concentrations of TCNM were formed. The formation potential of TCNM was impacted by operational conditions and water matrix components: (1) high pH enhanced TCNM formation; (2) high UV fluence inhibited TCNM formation; and (3) organic compounds containing phenolic groups enhanced TCNM formation. We discovered that electrophilic substitutions by reactive nitrogen species were favored for phenolic groups, and thus more nitrite-N was transformed to organic nitrogen. We also found that more TCNM was generated from natural organic matter than algal organic matter during chlorination following pretreatment using UV/PS. Accordingly, more attention needs to be paid to TCNM formation, if nitrite is present and the water is pretreated using UV/PS (when applied at upstream of chlorination). For example, we found that if monochloramine was used as a disinfectant downstream of the UV/PS process, the formation of TCNM was reduced.
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•Large amount of TCNM was formed in UV/PS + chlorination in the presence of nitrite.•Presence of phenolic group favors for the above-formed TCNM.•Nitrite is mainly transformed to organic nitro-group during the UV/PS process.•NH2Cl can reduce the above-mentioned formation of TCNM compared to Cl2.
The main goal of this work was to estimate the influence of carboxyl and phenolic groups, as well as aromatic, aliphatic and polysaccharide components, on the soil humic acids (HA) self-aggregation ...process. Soil HAs (leptosol and regosol) were separated using base resin getting fractions with different functional group contents. Blocking of carboxyl groups was performed using the esterification procedure to estimate the participation of each functional group in the HA aggregation. The presence of HA structural components was evaluated by potentiometric titration and ATR-FTIR. The aggregation was monitored at pH 3 using dynamic light scattering. Results indicated that the higher group content, the HA aggregation is less pronounced. A significant positive correlation of aliphatic C and aggregate size revealed their dominant influence in the HA self-aggregation. A lower abundance of aliphatic C in HA fractions could be considered as not sufficient to start the process. An increase of aromatic C in esters likely pointed out to its participation in hydrophobic bonding and, consequently, more pronounced aggregation. The relation of HA self-aggregate size with carboxyl and phenolic group, as well as aliphatic C, at low pH, could be considered universal regardless of the structural characteristics of the original or modified HA forms.
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•Phenolic series of indenopyridinone were synthesized.•SAR study was performed by comparing topo inhibitory and anti-proliferative activity.•para-Phenolic group at 2- and/or ...4-position of indenopyridinones is important.•Compound 12 acted as DNA-intercalative potent topo IIα inhibitor.•Indenopyridinone as potential scaffold for anticancer activity.
DNA Topoisomerase IIα (topo IIα) is one of the most effective therapeutic targets to control cancer. In an effort to develop novel and effective topo IIα targeting anti-proliferative agent, a phenolic series of indenopyridinone and indenopyridinol were designed and prepared using efficient multi-component one pot synthetic method. Total twenty-two synthesized compounds were assessed for topo I and IIα inhibition, and anti-proliferation in three different human cancer cell lines. Overall structure-activity relationship study explored the significance of meta-phenolic group at 4-position and para-phenolic group at 2- and/or 4-position of indenopyridinone skeleton for strong topo IIα-selective inhibition and anti-proliferative activity against human cervix (HeLa) and colorectal (HCT15) cell lines. Compound 12 with excellent topo IIα inhibition (93.7%) was confirmed as a DNA intercalator that could be a new promising lead to develop effective topo IIα-targeted anticancer agents.
A series of supported Wacker-type catalysts under treatment of nitric acid were prepared and utilized in the synthesis of dimethyl carbonate from CO and methyl nitrite. Nitrogen adsorption, Boehm ...titration, scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and H2-temperature-programmed reduction (H2-TPR) were employed to explore the relationship between the physicochemical properties and reactivity of catalysts. Correlated with the results of Boehm titration, it was found that catalytic activities increased monotonically with the number of phenolic group on activated carbon surface. XPS spectra showed that the catalysts, which had much more amount of phenolic group, were possessed of large amount of Cu2+ species. H2-TPR results indicated that the phenolic group contributed to the easier reducibility of Cu2+ species, further facilitating the oxidation cycle between Pd and Cu species and consequently the catalytic performance.
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•The catalytic performances of PdCl2–CuCl2/AC catalysts were proven to be affected by the surface chemistry of AC.•The phenolic group of AC contributed to the Cu2+ species of Wacker-type catalysts.•The surface phenolic group of AC was favorable for improving the catalytic activity for dimethyl carbonate.
The influence of lignin species on the grafting mechanism of lignosulfonate (from eucalyptus and pine, recorded as HLS and SLS, respectively) with acrylic acid (AA) was investigated. The graft ...polymers were confirmed by the absorption of carbonyl groups in the FTIR spectra. The decreasing phenolic group's content (Ph-OH) is not only due to its participation as grafting site but also to the negative effect of initiator. In the initial period (0–60min), HLS and SLS both accelerate the polymerization of AA. Additionally, Ph-OH group's content is proportional to product yield (Y%), monomer conversion (C%) and grafting efficiency (GE%), strongly indicating that it acts as active center. Nevertheless, compared with HLS, Y% and C% in SLS grafting system are lower though it has higher Ph-OH group's content, which is due to the quinonoid structure formed by the self-conjugated of phenoxy radical in Guaiacyl unit. Finally, the lignosulfonate grafting mechanism was proposed.
Inspired by the importance of the phenolic group to the electron transporting property of hole transport materials, phenolic hydroxyl groups were introduced in lignosulfonate (LS) via the alkyl chain ...bridging method to prepare phenolated-lignosulfonate (PLS). The results showed that the phenolic group was boosted from 0.81 mmol·g
−1
of LS to 1.19 mmol·g
−1
of PLS. The electrochemical property results showed two oxidation peaks in the cyclic voltammogram (CV) curve of PLS, and the oxidation potential of the PLS-modified electrode decreased by 0.5 eV compared with that of LS. This result indicates that PLS is more easily oxidized than LS. Based on the excellent electron transporting property of PLS, PLS was applied as a dopant in poly(3,4-ethylenedioxythiophene) (PEDOT, called PEDOT:PLSs). PLS showed excellent dispersion properties for PEDOT. Moreover, the transmittance measurement results showed that the transmittance of PEDOT:PLSs exceeded 85% in the range of 300–800 nm. The CV results showed that the energy levels of PEDOT:PLSs could be flexibly adjusted by PLS amounts. The results indicate that the phenolic hydroxyl group of lignin can be easily boosted by the alkyl chain bridging method, and phenolated lignin-based polymers may have promising potential as dopants of PEDOT to produce hole transporting materials for different organic photovoltaic devices.
The formation and modification of inter- and intramolecular hydrogen bonds of hydroxyl (phenolic group) terminated hyperbranched aromatic polyesters (HBP-OH) have been studied by ...temperature-dependent Fourier transform infrared (FTIR) spectroscopy. Three ‘heating–annealing–cooling’ (HAC) cycles starting from room temperature to 235
°C were measured. The IR spectroscopic results indicate different types of hydrogen bond association. The weakening and breaking of hydrogen bonds with increasing temperature was observed. Additionally, a curve fitting procedure of the hydroxyl and carbonyl vibration regions has been done to gather additional information of the hydrogen bond association. On the basis of the band shifts and the changes of the normalised integral band intensity (NIBI) and halfwidth of a band (HWB), the formation of a network of hydrogen bonds was proposed. Four different interactions regarding hydroxyl (phenolic) groups association were detected. Several types of associated carbonyl groups existing within HBP-OH were revealed. The spectra and curve fitting results indicate the relative stability of formed bond structures with participation of the ester groups of the HBP rigid segments in the studied temperature region. Differential scanning calorimetry (DSC) was applied to reveal changes in thermal behaviour after the first, the second and the third HAC cycle. As expected, the aromatic ester backbone structure strongly influences the glass transition. Therefore, the performed measurements did not show any changes in glass transition related to the rearrangements in the hydrogen bonded network.
Core Ideas
Cu‐Pb‐Zn tailings have different humic acid adsorption capacity.
Fresh tailings contain more Fe/Al‐oxyhydroxides and adsorbed more humic acids.
Carboxylic and phenolic groups of HA ...preferentially interacted with mineral particles in tailings.
Acidic pH conditions favor humic acid adsorption in the tailings.
Aggregation of tailings is instrumental for developing a physical environment permitting water infiltration, aeration, and root penetration. Previous research found that microaggregation of Cu‐Pb‐Zn tailings was stimulated by amendment of composted sugarcane residues. The present study aimed to identify organic functional groups in humic acids (HA) involved in the aggregation of Cu‐Pb‐Zn tailings, which were considered to be formed from long‐term organic matter decomposition in the engineered tailing‐soil. The adsorption of HA by the weathered (WT) and freshly deposited (FT) tailings was evaluated at a range of pH conditions in tailing‐HA suspension. Humic acid adsorption decreased with increasing pH from 5.0 to 9.0. The FT was found to contain more oxy‐(hydr)oxides, particularly poorly crystalline Fe and Al oxy‐(hydr)oxides than the WT, which was one of the factors attributing to FT's higher HA affinity. The Fourier transform infrared spectroscopy analysis of tailing particles before and after HA adsorption indicated that carboxylic and phenolic groups of HA preferentially interacted with tailing mineral particles, probably through ligand exchange, polyvalent cation bridge and electrostatic attraction. The pH‐dependent HA adsorption indicated the potential role of functional groups of organic matters in microaggregation of Cu/Pb‐Zn tailings. Moreover, the presence of abundant Al/Fe oxyhydroxides promoted organo‐mineral interactions. The present findings will contribute toward developing field application to engineer functional Technosols from the tailings by selecting organic matter rich in functional groups.
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