Synergetic Effect Of Adsorption Research Articles

Biochar-enhanced anaerobic mixed culture for biodegradation of 1,2-dichloroethane: Microbial community, mechanisms, and techno-economics

While anaerobic digestion (AD) has been employed for the degradation of chlorinated aliphatic hydrocarbons, the associated digester performance might suffer from volatile fatty acids accumulation, insufficient substrate-microbes interaction, and lower biogas yields. To overcome these limitations, this study is the first to augment the hydrocarbon-degrading microbial capacities by adding agricultural waste-based biochar to the digestion medium. 1,2-dichloroethane (1,2-DCA) was selected as the target pollutant because it is discharged in large quantities from oil refining, petrochemical, and chemical industries, causing serious environmental and human health concerns. A multi-chamber anaerobic reactor (MAR) was operated at a 1,2-DCA loading rate of 1.13 g/L/d, glucose dosage (as an electron donor) range of 200–700 mg/L, and hydraulic retention time of 11.2 h, giving dechlorination = 32.2 ± 6.9% and biogas yield = 210 ± 30 mL/g CODremoved. These values increased after biochar supplementation (100 mg/g volatile solids, VS, as an inoculum carrier) up to 60.2 ± 11.5% and 290 ± 40 mL/g CODremoved, respectively, owing to the enhancement of dehydrogenase enzyme activities. Burkholderiales (15.3%), Clostridiales (2.3%), Bacteroidales (3.5%), Xanthomonadales (3.3%), and Rhodobacterales (6.1%) involved in 1,2-DCA degradation were dominant in the reactor supplemented with biochar. It's suggested that biochar played a major role in facilitating the direct interspecies electron transfer (DIET) between syntrophic bacteria and methanogens, where chloride, ethylene glycol, and acetate derived from 1,2-DCA dechlorination could be further used to promote methanogenesis and methane production. The synergetic effect of adsorption and dechlorination towards 1,2-DCA removal was validated at various biochar dosages (50–120 mg/g) and 1,2-DCA concentrations (50–1000 mg/L). The techno-economic results showed that the cost of treating 1,2-DCA-laden discharge (100 m3/d) by the MAR module could be 0.83 USD/m3 with a payback period of 6.24 years (NPV = 2840 USD and IRR = 10%), retrieving profits from pollution reduction (9542 USD/yr), biogas selling (10418 USD/yr), and carbon credit (10294 USD/yr).

Layered by layered construction of three novel ZnCo-LDHs/g-C3N4 for the removal of sunset yellow by adsorption-photocatalytic process.

The removal of organic dyes has attracted attention by adsorption-photocatalytic synergetic process in water treatment technology. Three novel ZnCo-LDHs/g-C3N4 were successfully prepared for the first time by layered construction technique through the hydrolysis of triethanolamine in this paper. They exhibited high specific surface area which facilitates the adsorption of sunset yellow (SY) from solution to catalyst surface. All the target pollutant dyes are very effectively removed by the three ZnCo-LDHs/g-C3N4 composites through synergetic effect of adsorption and photocatalysis process under UV irradiation (λ = 365nm). The order of synergistic degradation effect for SY is as follows: ZnCo-LDHs/g-C3N4-3 (99.6%) > ZnCo-LDHs/g-C3N4-2 (99.5%) > ZnCo-LDHs/g-C3N4-1 (99.3%) > pure g-C3N4 (77.4%) > pure ZnCo-LDHs (44.2.6%) at the initial concentration of 75mg L-1. ZnCo-LDHs/g-C3N4-3 has the largest k value (0.0284min-1) in SY degradation, which is 2.8 times that of g-C3N4. ZnCo-LDHs/g-C3N4-3 is a very promising adsorption-photocatalyst for the removal of SY from wastewater. The electron spin resonance experiments demonstrate that OH·, 1O2, and O2- are the dominant active species and oxides SY together. This result demonstrates that the three ZnCo-LDHs/g-C3N4 have practical applications as efficient adsorption-photocatalytic materials and also provides a synergetic strategy for the removal of SY wastewater.

Synergetic effect of adsorption and photocatalysis by zinc ferrite-anchored graphitic carbon nitride nanosheet for the removal of ciprofloxacin under visible light irradiation

Abstract Ciprofloxacin (CIP) belongs to the fluoroquinolone antibiotic family. It is mostly used for the treatment of bacterial infections and highly recalcitrant to naturally decompose. The nanocomposite was successfully constructed by zinc ferrite nanoparticle anchored onto graphitic carbon nitride nanosheet (ZFNP–CNNS). The structural, morphological, and optical properties of the ZFNP–CNNS nanocomposite were investigated. Moreover, the enhanced photocatalytic performance of the ZFNP–CNNS nanocomposite was a result of the synergetic effect between adsorption and photocatalysis. The adsorption study showed that the ZFNP–CNNS nanocomposite has heterogeneous active sites with multilayers and the maximum CIP adsorption capacity was 15.49 mg g−1. However, the photodegradation efficacy of CIP reached up to five times compared to that of pristine CNNS. The high adsorption–photocatalytic synergetic effect of the ZFNP–CNNS nanocomposite has great application in wastewater treatment.

Nature-based nanocomposites for adsorption and visible light photocatalytic degradation of methylene blue dye

Demands for sustainable and eco-friendly materials for environmental remediation have increased the interest in bio-reinforced nanocomposites. Herein, novel plant extracts modified polyvinyl alcohol (PVA) nanocomposite films were fabricated using Hemp seeds, St. John's Wort, Rosemary, and Cherry Laurel plants, and their photocatalytic activities were investigated for the photodegradation of Methylene Blue (MB) dye. Besides, bio-reinforced nanocomposites were characterized by various techniques to investigate the influence of plant extracts on the chemical structure, morphology, hardness, and swelling ratio of nanocomposite films. The morphological inspections revealed that as a result of the plant-extract modification, the PVA matrix was reinforced with equiaxed nanoparticles in a size range from 20 to 250 nm. The Shore-D hardness and the water absorption capacities of fabricated bio-reinforced nanocomposites were found to be 1.86 and 1.24 times higher than their neat counterparts, respectively. Both the bio-reinforced nanocomposites films showed considerably enhanced photocatalytic activity for MB dye degradation relative to neat PVA film. With a synergetic effect of adsorption and photocatalytic degradation, 61.3% of MB dye could be removed under light irradiation by Rosemary and Cherry Laurel modified PVA nanocomposite film. Therefore, the present bio-reinforced nanocomposites with photocatalytic activity shed light on the unknown potential of plant extracts.

Dewatering Treatment and Catalytic Application of Sludge by Glow Discharge Plasma

In this paper, glow discharge plasma (GDP) was used to remove organic contaminants of sludge and improve sludge dewaterability. Fe-rich sludge as a catalyst combined GDP to form heterogeneous Fenton reaction, which was used to remove 2,4-dichlorophenoxyacetic acid (2,4-D) in aqueous solution. The surface micrographs and chemical composition of Fe-rich sludge was analysed by the Scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS). The effect of initial pH0 on hydrogen peroxide (H2O2) yield in GDP was discussed. The removal of 2,4-D was associated with the synergetic effect of adsorption and oxidative, and hydroxyl radicals (•OH) play a dominant role. This study provides an environmentally-friendly technology to improve sludge dewaterability and a potentially low-cost catalyst for 2,4-D removal in water, which is significant for the reuse of Fe-rich sludge.

Photocatalytic Treatment of Methyl Orange Dye Wastewater by Porous Floating Ceramsite Loaded with Cuprous Oxide

It is well known that water treatment of printing and dyeing wastewaters is problematic. In order to decompose dyes from dyestuff wastewater and convert them into almost harmless substances for the natural environment, an easily prepared, efficient, practical, and easy-to-regenerate composite material was produced from porous floating ceramsite loaded with cuprous oxide (PFCC). The PFCC samples were prepared and characterized by X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The material was applied for photocatalytic degradation of methyl orange (MO) in water. The results show that the maximal degradation rate of MO was 92.05% when the experimental conditions were as follows: cuprous oxide loading rate of 8%, PFCC dosage of 20 g/L, the reaction time of 2 h, pH value of 8, and solution initial concentration of 30 mg/L. The degradation processes of MO fits well with the Langmuir–Hinshelwood model in reaction kinetics, and the Freundlich model in reaction thermodynamics, respectively. The degradation mechanism of MO was considered from two perspectives—one was the synergetic effect of adsorption and photocatalytic oxidation, and the other was the strong oxidation of hydroxyl radicals produced by photocatalysts.

Construction of stable perovskite-type LaFeO3 particles on polymeric resin with boosted photocatalytic Fenton-like decaffeination under solar irradiation

In this work, LaFeO3 perovskite particles were successfully immobilized on the commercial polymeric resin (Amberlite XAD-4) to yield a novel and applicable photocatalyst. The prepared catalysts were systematically characterized by XRD, XPS, FTIR, SEM, TEM-EDX, UV-DRS, PL and TGA analyses. It is demonstrated that LaFeO3 particles (LFO) with well crystallinity were immobilized onto the surface of resin, leading to the formation of composite LFO/XAD4 catalyst. The signals of La 3d, Fe 2p and O 1s on the composite were further confirmed by the XPS spectroscopy. The photocatalytic, Fenton and photo-Fenton performances of the samples were investigated by degrading caffeine under visible light illumination. Such an immobilization of the LaFeO3 particles onto the resin significantly altered the photocatalytic and photo-Fenton degradation of caffeine; the photo-Fenton degradation rate in the presence of the bare LaFeO3 (41.5%) enhanced to 78.5% after immobilization suggesting that the synergetic effect of adsorption and photocatalysis played a major role in the decaffeination process. Moreover, the increasing LaFeO3 ratio to a certain level over the resin surface greatly improved the degradation which could be resulted in more absorption of light radiation and enhanced transfer of the photo-induced electrons. The photo-Fenton catalytic mechanism under sun light illumination was also discussed in terms of solution pH, H2O2 concentration, co-existing anions and scavengers. In addition, reusability tests revealed that the immobilization also eases the separation and stability of the catalyst which can be effectively used until sixth cycle. The degradation pathways of photo-Fenton degradation of CAF were proposed. This work gives an insight into the usage of polymeric resins as potential supporting materials in the photocatalysis field.

The synthesis of heterogeneous Fenton-like catalyst using sewage sludge biochar and its application for ciprofloxacin degradation

The terminal utilization of sewage sludge biochar (SSB) is nonnegligible and significant for sewage sludge (SS) treatment by pyrolysis. In this paper, a novel low-cost recyclable sludge biochar catalyst (SBC) that can be employed as a heterogeneous Fenton-like catalyst was prepared using SSB from SS pyrolysis in a pilot-scale platform for ciprofloxacin (CIP) degradation. The fabricated SBC was analyzed to characterize its surface micrographs, pore structures, and chemical composition. The catalytic effect of SBC on CIP degradation was also explored to determine the feasibility of using SBC to remove aquatic organic contaminants, and its degradation mechanism and pathway were also discussed. SBC can effectively remove CIP by adsorption and enhance the degradation of CIP by its catalytic effect. >80% of the CIP was removed at pH 4.0, and the antimicrobial activity of the resulting products was considerably reduced. The possible degradation mechanism is associated with the synergetic effect of adsorption and oxidative degradation. Oxidizing radical was generated from H2O2 by the activation of Fe2+ and Fe3+, which released from SBC, and HO was the dominant radical in CIP degradation. Piperazine ring cleavage, pyridine cleavage and hydroxylation, F/OH substitution, and defluorination were the dominant degradation pathways. The heavy metal risk assessment showed that SBC exhibits low environmental and ecological risk. This study provides a prospective method for high-value utilization of SSB and a novel and potentially low-cost catalyst for CIP removal from aqueous environments, which is significant for the terminal disposal of SS.

Metal-organic framework-based mixed matrix membranes: Synergetic effect of adsorption and diffusion for CO2/CH4 separation

ZIF-8 nanoparticles were doped into P84 polymer matrix to synthesize defect-free mixed matrix membranes (MMMs) for CO2/CH4 separation. A remarkable combination of gas permeability and separation factor appeared in MMMs with filler loading of 27 wt%. The permeability of CO2 achieved 10.92 Barrers along with CO2/CH4 separation factor of 92.6, separately corresponding to an increment of 339% and 35.7% compared with the pure P84 membrane, which breaks the trade-off between permeability and selectivity of polymer membranes. Adsorption and diffusion coefficient of CO2 and CH4 for ZIF-8/P84 MMMs as well as the apparent activation energy of the corresponding processes were quantitatively determined, indicative of a synergetic effect of the selective adsorption and molecular sieving property arising from ZIF-8 nanoparticle fillers on the significant improvement of separation performances.

One-pot synthesis of Mn-doped TiO2 grown on graphene and the mechanism for removal of Cr(VI) and Cr(III)

Mn-doped TiO2 grown on reduced graphene oxide(rGO) was synthesized by one-pot hydrothermal method and the photocatalytic removal of Cr by the material was investigated under sunlight. The materials were characterized by a combination of scanning electron microscopy, transmission electron microscopy, X-ray diffraction, thermogravimetric analysis, Brunauer-Emmett-Teller method, UV–vis diffuse reflectance spectra, photoluminescence spectra, electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy. Cr(total) removal efficiency of the material is 97.32% in 30min and 99.02% in 60min under sunlight irradiation, as the initial concentration of Cr(VI) is 20mg/L. The high photocatalytic activity under visible light is considered mainly due to the Mn-doping, and rGO plays an important role in the synergetic effect of adsorption and photocatalysis to sustain the high efficient removal of Cr(VI) and Cr(III). Cr(VI) adsorbed on the surface of rGO is reduced to Cr(III) by photo electrons which are transported through rGO, and the reaction product Cr(III) continues to be adsorbed. The process contributes to the release of abundant photocatalytic sites of Mn-TiO2 and improves photocatalytic efficiency. The excellent adsorption and photocatalytic effect with the explanation of the synergetic mechanism are very useful not only for fundamental research but also for the potential practical applications.

Highly Monodisperse NiO QDs Embedded in rGO Sheets: Synergetic Effect of Adsorption and Antibacterial Properties in Water Treatment

In this paper, the hybrid composite of NiO quantum dots (QDs) ∼2 nm in diameter embedded in reduced graphene oxide (rGO) nanosheets with an average thickness of 1 nm was synthesized by a one-pot facile wet chemical method. The cost was reduced using NiO instead of Ag NPs, and the embedded NiO QDs can prevent the rGO sheets from aggregation, maintaining their high surface area and active sites. The NiO-rGO composite was used as adsorbent for phage f2 and MS2, and the adsorption capacity could be up to 107 PFU/mg with removal efficiency for MS2 up to ∼90 % in 30 minutes, while that for f2 up to ∼80% in 20 minutes. The composite also showed antibacterial properties towards E. coli. Paper disk diffusion assay, MIC and MBC tests revealed good antibacterial properties of the NiO-rGO composite. The synergetic effects on both phage adsorption and antibacterial properties would make the cheap NiO-rGO hybrid composite usable in water treatment.

Synergetic effect of adsorption on degradation of malachite green dye under blue LED irradiation using spiral-shaped photocatalytic reactor

BACKGROUND The present study focus on the development and feasibility of a blue light emitting diodes (LEDs) source based slurry type spiral-shaped photocatalytic reactor for degradation of malachite green (MG) dye using P25 Degussa TiO2. The influence of operational parameters such as amount of catalyst loading, initial concentration of dye, and pH of the medium has been studied for optimization of MG dye degradation. RESULTS The photocatalytic degradation of malachite green dye under separate irradiation by blue and by ultraviolet LED was nearly the same (∼76%). The photocatalytic activity using blue LED irradiation was observed due to the synergistic effect of MG dye adsorption on P25 Degussa, which extends the spectral response of TiO2 to the visible region (449 nm). The optimized degradation of 20 mg L-1 dye was observed at pH 8 using 0.5 g L-1 of catalyst under irradiation by ultraviolet and blue LEDs for 1 h and 3 h, respectively. CONCLUSION It was found that the synergistic effect of adsorption of malachite green dye on TiO2 surface helped to enhance photocatalytic degradation under blue LED irradiation. The application of a blue LED for photocatalytic degradation of malachite green dye is economical and feasible compared with use of an ultraviolet LED. © 2014 Society of Chemical Industry

Stable photocatalytic activity of immobilized Fe 0/TiO 2/ACF on composite membrane in degradation of 2,4-dichlorophenol

To increase the activity of immobilized catalyst by synergetic effect of adsorption and to extend the activity of Fe 0, a composite membrane with Fe 0, activated carbon fiber (ACF) and TiO 2 was prepared, using dip-coating, impregnation and chemical reduction methods. The activity of the prepared membrane was evaluated for mineralizing 2,4-dichlorophenol (2,4DCP) in water under UV illumination. The co-presence of Fe 0 and TiO 2 enhanced 2,4DCP degradation. ACF addition and its adsorption effect were shown in promoting 2,4DCP mineralization and TOC removal by comparing activities of composite membranes with Fe 0/TiO 2/ACF or Fe 0/TiO 2. Effects of pH and iron loading ratio to TiO 2 on degradation rate of 2,4DCP using the composite membrane were investigated and optimized. The optimal pH was 6 and the optimal loading of Fe 0 was 1 wt% to TiO 2. The repeated test results and XRD patterns of catalysts before and after reaction proved that the Fe 0/TiO 2/ACF membrane was durable and stable in its photocatalytic activity.

Photocatalytic activities and mechanism of the supercritically treated TiO2-activated carbon composites on decomposition of acetaldehyde

The supercritically treated TiO2-activated carbon (Sc-TiO2-AC) composites were studied for their adsorption and subsequent photocatalytic activities for acetaldehyde. Sc-TiO2-AC composites showed much higher decomposing ability for acetaldehyde compared to a noncomposite comprising a simple mixture of activated carbon and TiO2. This indicates that Sc-TiO2-AC composites have a synergetic effect of adsorption and photocatalytic decomposition of acetaldehyde. Meanwhile, acetaldehyde was found to be decomposed to CO2 as final product by Sc-TiO2-AC composites through the conversion to methanol, formaldehyde and acetic acid as intermediates. It was also found that many OH groups exist on the Sc-TiO2-AC composites. These OH groups can be assumed to take part in the photocatalytic degradation of acetaldehyde.