Sulfur/zinc co-doped biochar for stabilization remediation of mercury-contaminated soil: Performance, mechanism and ecological risk.

In this study, a novel sulfur/zinc co-doped biochar (SZ-BC) stabilizer was successfully developed for the remediation of mercury-contaminated soil. Results from SEM, TEM, FTIR and XRD revealed that biochar (BC) was successfully modified by sulfur and zinc. In the batch adsorption experiments, the sulfur-zinc co-pyrolysis biochar displayed excellent Hg(II) adsorption performance, with the maximum adsorption capacity of SZ-BC (261.

Phosphorus-modified biochar cross-linked Mg-Al layered double-hydroxide stabilizer reduced U and Pb uptake by Indian mustard (Brassica juncea L.) in uranium contaminated soil.

The decommissioning of uranium tailings (UMT) is usually accompanied by uranium (U) contamination in soil, which poses a serious threat to human health and ecological security. Therefore, the remediation of uranium pollution in soil is imminent from ecological and environmental points of view. In recent years, the use of biochar stabilizers to repair uranium tailings (UMT) soil has become a research hotspot.

Highly efficient photocatalytic oxidation of antibiotic ciprofloxacin using TiO@g-CN@biochar composite.

In this present study, a novel indirect Z-scheme TiO@g-CN@biochar (TiO@g-CN@BC) composite photocatalyst was successfully fabricated and characterized with SEM, TEM, EDS, XRD, FTIR, PL, XPS, and UV-vis DRS. The photocatalytic degradation behavior of ciprofloxacin (CIP) on the TiO@g-CN@BC was evaluated under UV-vis and visible light irradiation, and the possible reaction mechanism of photocatalytic oxidation of CIP on the TiO@g-CN@BC was explained. The TiO@g-CN@BC composite photocatalyst exhibited stronger photocatalytic oxidation activity for CIP in comparison with TiO, g-CN, TiO@BC, and TiO@g-CN.

Enhanced phytoremediation of uranium-contaminated soils by Indian mustard (Brassica juncea L.) using slow release citric acid.

In this study, a novel slow release carrier for the controlled release of citric acid (CA), hydroxypropyl chitosan-graft-carboxymethyl-β-cyclodextrin (HPCS-g-CMCD) was synthesized by the grafting reaction of carboxymethyl-β-cyclodextrin (CMCD) with hydroxypropyl chitosan (HPCS), and the structural characteristics of HPCS-g-CMCD were confirmed by FT-IR, TGA, and NMR. Based on HPCS-g-CMCD and CA, slow release citric acid (SRCA) was prepared by a spray drying method. HPCS-g-CMCD carrier has a better slow release performance for CA compared to HPCS and CMCD, and CA release mechanism was attributed to a Fickian diffusion.

Phosphorus-modified biochar cross-linked Mg-Al layered double-hydroxide composite for immobilizing uranium in mining contaminated soil.

The decommissioning of uranium mill tailings (UMTs) is usually accompanied by uranium (U) contamination in soil, which poses a serious threat to human health and ecological safety. In this study, a novel phosphorus-modified bamboo biochar (PBC) cross-linked Mg-Al layered double-hydroxide (LDH) composite ("PBC@LDH") was successfully prepared by phosphate pre-impregnation and a hydrothermal method with Mg-Al LDH. Physicochemical analysis revealed that phosphorus-containing functional groups and Mg-Al LDH were grafted onto the pristine biochar (BC) matrix.

Adsorption of dichromate ions from aqueous solution onto magnetic graphene oxide modified by β-cyclodextrin.

In this work, the β-cyclodextrin modified magnetic graphene oxide (β-CD/MGO) composite was fabricated by the in situ co-precipitation method and characterized by Fourier transform-infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM), and particle size analysis. The adsorption behavior of dichromate ions on the β-CD/MGO was investigated, and the mechanism of adsorption was also studied using FT-IR and XPS. The results from SEM and TEM showed that the graphene oxide (GO) layer became rough, and many fine particles were attached after compounding with ferroferric oxide and β-cyclodextrin.

Enhanced photocatalytic New Coccine degradation and Pb(II) reduction over graphene oxide-TiO composite in the presence of aspartic acid-β-cyclodextrin.

In this work, aspartic acid-β-cyclodextrin (ACD) was synthesized by the reaction of β-cyclodextrin with aspartic acid and epichlorohydrin, and graphene oxide-TiO (GO-TiO) composite catalyst was prepared by a hydrothermal method. The complexation of ACD with New Coccine (NC) and Pb was characterized with FT-IR and XPS, respectively, the results show that ACD can simultaneously complex NC and Pb. XRD analysis and SEM images of GO-TiO show that TiO platelets are well distributed on both sides of the graphene oxide sheets, and display a similar XRD pattern to the pure TiO nanoparticles with the typical diffraction peak of anatase phase.

Cysteine-β-cyclodextrin enhanced phytoremediation of soil co-contaminated with phenanthrene and lead.

It is necessary to find an effective soil remediation technology for the simultaneous removal of hydrophobic organic contaminants and heavy metals from contaminated soils. In this work, a novel cysteine-β-cyclodextrin (CCD) was synthesized by the reaction of β-cyclodextrin with cysteine, and the structure of CCD was confirmed by (1)H-NMR, (13)C-NMR, FT-IR spectroscopy and elemental analysis. Pot-culture experiments were conducted to investigate the effects of CCD on the phytoremediation of soil co-contaminated with phenanthrene and lead.

β-Cyclodextrin's orientation onto TiO2 and its paradoxical role in guest's photodegradation.

This work revealed that β-cyclodextrin was attached onto the surface of TiO(2) predominately by its secondary ring side, which caused paradoxical functions of β-cyclodextrin in the photodegradation of the four bisphenols. The equilibrium between the guest adsorbed through β-cyclodextrin onto TiO(2) and the one locked in β-CD in water could also change the role of β-cyclodextrin in the degradation of a certain guest.

Photodegradation of E2 in the presence of natural montmorillonite and the iron complexing agent ethylenediamine-N,N'-disuccinic acid.

In this work, the photochemical degradation process of 17β-estradiol (E2) in a suspension of natural montmorillonite (NM) has been studied. The addition of the iron complexing agent ethylenediamine-N,N'-disuccinic acid (EDDS) to the suspension was investigated and compared with the system without EDDS. The effects of the main physicochemical parameters (pH, EDDS, oxygen and NM concentrations) on E2 degradation in NM suspensions were also investigated.

Intermediates in photochemistry of Fe(III) complexes with carboxylic acids in aqueous solutions.

The primary processes in the photochemistry of Fe(III) complexes with carboxylic acids (glyoxalic, tartaric, pyruvic and lactic) were studied by means of laser flash photolysis. The inner-sphere electron transfer with the formation of Fe(II) complex and an escape of an organic radical to the solution bulk was shown to be a minor channel of the photolysis. The main channel was proposed to be the formation of a long-lived radical complex [Fe(II)···˙OOC-R](2+).

Efficient photodegradation of dyes using light-induced self assembly TiO(2)/β-cyclodextrin hybrid nanoparticles under visible light irradiation.

A novel β-cyclodextrin (β-CD) grafted titanium dioxide (TiO(2)/β-CD) was synthesized through photo-induced self assembly methods, and its structure was characterized. The TiO(2)/β-CD hybrid nanomaterial showed high photoactivity under visible light irradiation (λ ≥ 400 nm and/or λ ≥ 420 nm) and simulated solar irradiation (λ ≥ 365 nm). Photodegradation of Orange II followed the Langmuir-Hinshelwood kinetics model.

Simultaneous removal of phenanthrene and lead from artificially contaminated soils with glycine-β-cyclodextrin.

Preparation of glycine-β-cyclodextrin (GCD) was carried out by the reaction of β-cyclodextrin with glycine in the presence of KOH and epichlorohydrin. The enhanced solubilization behavior of phenanthrene and lead carbonate by GCD was studied, and the desorption behavior of phenanthrene and lead from co-contaminated soil was also investigated. The results showed that GCD has obvious solubilization for phenanthrene and lead carbonate.

Photo-induced transformations of Hg(II) species in the presence of Nitzschia hantzschiana, ferric ion, and humic acid.

Effects of algae Nitzschia hantzschiana, Fe(III) ions, humic acid, and pH on the photochemical reduction of Hg(II) using the irradiation of metal halide lamps (lambda > or = 365 nm, 250 W) were investigated. The photoreduction rate of Hg(II) was found to increase with increasing concentrations of algae, Fe(III) ions, and humic acid. Alteration of pH value affected the photoreduction of Hg(II) in aqueous solution with or without algae.

[Study on the sorption of 4-octylphenol by freshwater algae].

The sorption of 4-octylphenol (4-OP) by two freshwater algae was investigated. Results showed that the sorption of 4-octylphenol by algae was obvious and quick, where 20% of initial 4-OP (2 mg/L) was accumulated by Chlorella vulgaris (CV) and 46% initial 4-OP (2 mg/L) was accumulated by Anabaena cylindrical (AC) after 5 min incubation. The sorption got equilibrium at 1 h after incubation.

Photodegradation of chloroform in aqueous solution: impact of montmorillonite KSF particles.

In this work, photodegradation of chloroform in water suspensions of montmorillonite KSF (KSF) under a black light lamp (lambda=365 nm) was investigated. The results showed that KSF induced the photodegradation of chloroform by producing hydroxyl radical (OH) that oxidized chloroform in the heterogeneous clay-water systems. The photodegradation of chloroform in KSF suspensions was greatly influenced by the concentration of KSF and the pH of KSF suspensions.

Photoinduced degradation of 2,4-dichlorophenol in water: influence of various Fe(III) carboxylates.

Fe(III)-carboxylate complexes were investigated with respect to tri-carboxylic (citric), di-carboxylic (tartaric) and mono-carboxylic (pyruvic) acids. In agreement with the chemical structure, results demonstrated that Fe(iii) was complexed by citric acid with a ratio of 1 : 1 (Fe/ligand), tartaric acid (d or l) with a ratio of 1 : 2 and by pyruvic acid with a ratio of 1 : 3. The iron concentration was fixed at 0.

Degradation of atrazine photoinduced by Fe(III)-pyruvate complexes in the aqueous solution.

The composition and photochemical properties of the Fe(III)-Pyr complexes in the aqueous solution was studied in this work. Fe(III) was complexed by Pyr in the ratio of 1:3. The photochemical processes occurred in the Fe(III)-Pyr system was studied in detail.

Adsorption of uranium (VI) from aqueous solution onto cross-linked chitosan.

Cross-linked chitosan (CCTS) was synthesized by the reaction of chitosan with epichlorohydrin under alkaline conditions. Adsorption of uranium (VI) from aqueous solution onto cross-linked chitosan was investigated in a batch system. Adsorption isotherm and adsorption kinetic studies of uranium (VI) onto cross-linked chitosan were carried out.

Influence of marine phytoplankton, transition metals and sunlight on the species distribution of chromium in surface seawater.

The photoreduction of Cr(VI) to Cr(III) by marine phytoplankton (diatoms, red and green algae), with or without the presence of transition metals (Fe(III), Cu(II) and Mn(II)) was studied. The direct influence of marine phytoplankton on the photochemical reduction of Cr(VI) was confirmed for the first time, and two kinds of mechanisms were suggested to be responsible for the species transformation: (a) Cr(VI) in excited state could be reduced by the electron donor in its ground state via photo produced electrons; and (b) the solvated electrons reduce the CrO(4)(2-) anions in their ground state. The conversion ratio of Cr(VI) to Cr(III) increased with increasing algae concentration and irradiation time.

Fenton-like oxidation of Rhodamine B in the presence of two types of iron (II, III) oxide.

The catalytic efficiency of iron (II, III) oxide to promote Fenton-like reaction was examined by employing Rhodamine B (RhB) as a model compound at neutral pH. Two types of iron (II, III) oxides were used as heterogeneous catalysts and characterized by XRD, Mössbauer spectroscopy, BET surface area, particle size and chemical analyses. The adsorption to the catalyst changed significantly with the pH value and the sorption isotherm was fitted using the Langmuir model for both solids.

Spectrophotometric determination of tungsten(VI) enriched by nanometer-size titanium dioxide in water and sediment.

The adsorption of W (VI) on different metal oxides (TiO(2), ZrO(2)), different crystal form of TiO(2) (rutile, anatase) with high surface areas was studied and compared under different pH. A novel method for preconcentration of W (VI) with nanometer size titanium dioxide (rutile) and determination by spectrophotometry has been developed. W (VI) was selective adsorbed on 100 mg TiO(2) from 250 ml solution at pH 3.

Photo-induced transformations of mercury(II) species in the presence of algae, Chlorella vulgaris.

The effects of algae (i.e., Chlorella vulgaris), Fe(III), humic substances, and pH on the photoreduction of Hg(II) under the irradiation of metal halide lamps (lambda>or=365 nm, 250 W) were investigated in this paper.

[Influence of cyclodextrins on the photodegradation of bisphenol A induced by Fe(III)].

Cyclodextrins (CDs) can form a host/guest inclusion complex with bisphenol A(BPA). Under a 250 W metal halide lamp (lambda > or = 365 nm), the effects of different cyclodextrins to oxidation of endocrine disrupter BPA in the Fe(III)-hydroxyl complexes system were investigated. In the presence of alpha- cyclodextrin or beta-cyclodextrin (alpha-CD or beta-CD), the photodegradation efficiency of BPA can be enhanced, but gamma-cyclodextrin (gamma-CD) showed inhibitive effect on the photodegradation efficiency.