scholarly journals Rapid Degradation of Carbon Tetrachloride by Microscale Ag/Fe Bimetallic Particles

2021 ◽  
Vol 18 (4) ◽  
pp. 2124
Author(s):  
Xueqiang Zhu ◽  
Lai Zhou ◽  
Yuncong Li ◽  
Baoping Han ◽  
Qiyan Feng
Keyword(s):  
Humic Acid ◽  
Catalytic Reduction ◽  
Direct Reduction ◽  
Cost Effective ◽  
Degradation Efficiency ◽  
Pseudo First Order Reaction ◽  
Solution Ph ◽  
Reaction Stage ◽  
Bimetallic Particles ◽  
Slow Reaction

Cost-effective zero valent iron (ZVI)-based bimetallic particles are a novel and promising technology for contaminant removal. The objective of this study was to evaluate the effectiveness of CCl4 removal from aqueous solution using microscale Ag/Fe bimetallic particles which were prepared by depositing Ag on millimeter-scale sponge ZVI particles. Kinetics of CCl4 degradation, the effect of Ag loading, the Ag/Fe dosage, initial solution pH, and humic acid on degradation efficiency were investigated. Ag deposited on ZVI promoted the CCl4 degradation efficiency and rate. The CCl4 degradation resulted from the indirect catalytic reduction of absorbed atomic hydrogen and the direct reduction on the ZVI surface. The CCl4 degradation by Ag/Fe particles was divided into slow reaction stage and accelerated reaction stage, and both stages were in accordance with the pseudo-first-order reaction kinetics. The degradation rate of CCl4 in the accelerated reaction stage was 2.29–5.57-fold faster than that in the slow reaction stage. The maximum degradation efficiency was obtained for 0.2 wt.% Ag loading. The degradation efficiency increased with increasing Ag/Fe dosage. The optimal pH for CCl4 degradation by Ag/Fe was about 6. The presence of humic acid had an adverse effect on CCl4 removal.

Comparison of Coal Ash and Activated Carbon for Removal of Humic Acid from Aqueous Solution

2013 ◽  
Vol 864-867 ◽  
pp. 1509-1512
Author(s):  
Xue Mei Zhang ◽  
Yan Zhang ◽  
Di Fan
Keyword(s):  
Aqueous Solution ◽  
Humic Acid ◽  
Activated Carbons ◽  
Removal Rate ◽  
Coal Ash ◽  
Cost Effective ◽  
Solution Ph ◽  
Adsorption Behaviors ◽  
Calcium Loading ◽  
Working Solution

This paper presents the adsorption behaviors of humic acid (HA) on coal ashes and powdered activated carbons (PACs). A bituminous coal, with or without calcium-loading, was used as a feedstock for coal ash preparation. The working solution of HA with a concentration of 20 mg/L was used in all adsorption tests. The results showed that calcium-enriched coal ash (CECA) gave rise to the removal rate of HA as high as 84.05%, much higher than those of raw coal ash (RCA) and PACs. The impacts of solution pH and adsorbent dosage on HA adsorption capacity were also investigated. It was found that lower pH facilitated to the removal of HA from aqueous solution by means of CECA, and the optimal CECA dosage was about 1.0g/L at pH 7.00. The data obtained in this study suggested that calcium-enriched coal ash could be useful and cost-effective in the treatment of wastewaters containing HA-like organic macro-molecules.

Effective Treatment of Humic Acid Foulants in SAGD Produced Water

2021 ◽  
Author(s):  
Chunli Li ◽  
Zhiwei David Yue ◽  
Xiaohong Tian ◽  
John Hazlewood
Keyword(s):  
Humic Acid ◽  
Humic Acids ◽  
Produced Water ◽  
Chelating Agent ◽  
Cost Effective ◽  
Efficiency Factor ◽  
Alcohol Ethoxylate ◽  
Major Type ◽  
Chemical Solution ◽  
Well Injectivity

Abstract Humic acids, one major type of organic foulants in steam assisted gravity drainage (SAGD) produced water, can precipitate on surface and downhole equipment in SAGD facilities, resulting in high cleaning costs, potential equipment damage and decrease of injectivity of disposal wells. In this paper, a cost-effective chemical solution is presented where an alcohol ethoxylate surfactant/chelating agent package can efficiently disperse the organic fouling molecules in SAGD produced water; therefore, the approach is expected to significantly mitigate the humic acid related fouling issues in the SAGD system. In this study, a variety of commercially available surfactant products were evaluated for their aids in well injectivity on humic acid molecules in the freshly obtained SAGD produced water. The lab testing filtration apparatus was specially designed to simulate the sandstone formation geology of SAGD disposal wells. An "efficiency factor" was defined to grade the dispersing performance of the surfactant and/or surfactant/chelating agent package in the lab filtration tests. The efficiency factor provides a reasonable estimation regarding how well the chemical can reduce the plugging risk in a disposal well as compared to the untreated produced water. Among all the surfactant products tested, an alcohol ethoxylate surfactant with the appropriate molecular structure shows distinguished dispersing performance on humic acids in SAGD produced water. However, the surfactant alone was found inconsistent in the dispersing performance when different batches of the produced water were involved. Inclusion of the specific metal chelating agents to the above surfactant formulation improved the dispersing performance consistency. The chelator molecules presumably help destroy the intermolecular bridges among humic acid molecules in the SAGD produced water; thereby, increasing the dispersing effectiveness of the alcohol ethyoxylate surfactants. Tests show that the efficiency factor of the surfactant/chelating agent package is higher than 8, which implies that the formulation could lead to eight times extension of the interval between workovers on SAGD disposal wells, a significant reduction for the operational downtime and costs. This study presented a cost-effective chemical solution to help disperse the humic acid molecules in SAGD produced water, which can help significantly reduce the fouling risk caused by organic foulants, improve injectivity and extend the intervals between workovers of SAGD disposal wells.

scholarly journals Green synthesis of the innovative super paramagnetic nanoparticles from the leaves extract of Fraxinus chinensis Roxb and their application for the decolourisation of toxic dyes

2019 ◽  
Vol 8 (1) ◽  
pp. 256-271 ◽  
Author(s):  
Imran Ali ◽  
Changsheng Peng ◽  
Dichu Lin ◽  
Iffat Naz
Keyword(s):  
Environmental Remediation ◽  
Degradation Mechanism ◽  
Pseudo First Order Reaction ◽  
Solution Ph ◽  
Factors Affecting ◽  
Toxic Dyes ◽  
Degradation Of Dyes ◽  
Stability Structure ◽  
Ft Ir ◽  
Fraxinus Chinensis

Abstract The leaves extract of Fraxinus chinensis Roxb was used for the synthesis of the innovative phytogenic magnetic nanoparticles (PMNPs) without adding toxic surfactants. The formation, morphology, elemental composition, size, thermal stability, structure and magnetic properties of these PMNPs were examined by UV-visible spectrophotometry, FT-IR, XRD, SEM, EDX, TEM, VSM, XPS, BET and TGA. The reactivity of the obtained PMNPs against decolourising toxic dyes, namely, malachite green (MG), crystal violet (CV) and methylene blue (MB), were investigated by UV-vis spectrophotometry. Further, the factors affecting the removal of dyes, including solution pH, adsorbent dosages, initial concentration of dyes, reaction temperature and contact time, were also investigated. The results revealed the decolourisation of 99.12% of MG and 98.23% of CV within 60 min, and 97.52% of MB within 200 min by the PMNPs using dyes concentration of 25 mg/l at pH 6.5 and 298.15 K. The kinetics outcome indicated that the degradation of dyes matched well to the pseudo first-order reaction kinetics model. Furthermore, the probable degradation mechanism of dyes by the PMNPs, including the adsorption of cationic dye molecules onto the negatively charged surface of adsorbent and the oxidation of the Fe° in the solution, were discussed. Thus, the PMNPs can be produced by the bulk and have great potential to be employed for biomedical/environmental remediation.

Coagulation of humic acid by ferric chloride in saline (marine) water conditions

2003 ◽  
Vol 47 (1) ◽  
pp. 41-48 ◽  
Author(s):  
J. Duan ◽  
N.J.D. Graham ◽  
F. Wilson
Keyword(s):  
Humic Acid ◽  
Zeta Potential ◽  
Membrane Filtration ◽  
Metal Salt ◽  
Substantial Effect ◽  
Precipitation Process ◽  
Solution Ph ◽  
Floc Size ◽  
Coagulant Dosage ◽  
Co Precipitation

The coagulation of a model seawater-humic acid solution with a hydrolysis metal salt (FeCl3) has been studied by monitoring floc size, solution pH, and zeta potential. The kinetic features of the orthokinetic coagulation have been demonstrated in relation to coagulant dosages, solution pH and zeta potential. Humic acid removal and floc charge reduction increased with coagulant dosage. Adjusting the solution pH prior to coagulation had a substantial effect on the treatment performance. By pH adjustment to pH 6, the greatest humic acid removal (by coagulation and subsequent membrane filtration) and the largest floc size was achieved at a FeCl3 dosage of 200 mmol l−1. It is believed that the coagulation is characterised by competition between OH- ions and humic acid for ferric ions in the co-precipitation process. In acidic pH, where the concentration of OH- ions is low, humic acid molecules may compete more favourably for bonding sites in the co-precipitation, which leads to a more compact precipitation and a higher overall humic acid removal.

The Effect of Operational Parameters on the Photocatalytic Mineralization of Indocorn Brilliant Red M5B Using Sol–gel Derived Nanostructured Zinc Titanate as an Efficient Photocatalyst

2012 ◽  
Vol 15 (2) ◽  
Author(s):  
Mohammad Hossein Habibi ◽  
Maryam Mikhak
Keyword(s):  
Azo Dye ◽  
Sol Gel ◽  
Degradation Efficiency ◽  
High Yield ◽  
Operational Parameters ◽  
Solution Ph ◽  
Zinc Titanate ◽  
First Order Kinetics ◽  
Size Uniformity ◽  
One Step

AbstractNanostructured zinc titanate (NZT) was synthesized in high yield via a one-step and template-free sol-gel route. The prepared nanocomposite exhibited good size uniformity and regularity. The enhanced photocatalytic activity of the NZT was evaluated in the degradation and mineralization of Indocorn Brilliant Red (M5B) under metal halide lamp irradiation. The effects of different parameters such as pH of the solution, and initial dye concentration on photodegradation of M5B were analyzed. The degradation of M5B follows pseudo-first order kinetics according to the Langmuir-Hinshelwood model. The experimental results showed that the initial concentration of azo dye in the dye mixture greatly affected the degradation efficiency. At M5B concentrations of 10 mg/L, the optimum conditions for the highest degradation efficiency (94%) of azo dye were a photocatalyst dosage of 0.01 g/L and an initial solution pH of 9. This study provided new insight into the design and preparation of nanomaterial demonstrated an excellent ability to remove organic pollutants in wastewater.

scholarly journals Comparative Studied of Degradation of Textile Brilliant Reactive Red Dye Using H2O2, TiO2, UV and Sunlight

2019 ◽  
Vol 22 (1) ◽  
pp. 31-36
Author(s):  
Forqan Mohammed ◽  
Khalid M. Mousa
Keyword(s):  
Reaction Time ◽  
Ambient Temperature ◽  
Uv Radiation ◽  
Advanced Oxidation Process ◽  
Oxidation Process ◽  
Textile Wastewater ◽  
Cost Effective ◽  
H2o2 Concentration ◽  
Solution Ph ◽  
Red Dye

In this study sunlight and UV radiation were used to compare the efficiency of decolorization of textile wastewater containing brilliant reactive red dye K-2BP (λmax = 534 nm) by the advanced oxidation process (AOP) using (H2O2/sunlight, H2O2/UV, H2O2/TiO2/sunlight, and H2O2/TiO2/UV). The results studied the effect of solution pH, applied H2O2 concentration, TiO2 concentration (nanoparticle), and initial dye concentration were studied. The experimental results showed that decolorization percentage with H2O2/sunlight and TiO2/H2O2/sunlight under the following conditions: - reaction time 150 of minutes, [ 500 ppm] H2O2, [100 ppm] TiO2, pH=3, initial dye concentration =15 ppm and at ambient temperature were 95.7% and 98.42% respectively. For the same conditions using H2O2/UV, H2O2/TiO2 /UV, the percentage of decolorization were 97.85% and 96.33% respectively. The results also indicated that the sunlight is more economic and cost-effective than UV radiation.

scholarly journals Magnetically recyclable Ag/TiO2 co-decorated magnetic silica composite for photodegradation of dibutyl phthalate with fluorescent lamps

2020 ◽  
Vol 81 (4) ◽  
pp. 790-800
Author(s):  
Zhiqiang Ding ◽  
Yue Liu ◽  
Yong Fu ◽  
Feng Chen ◽  
Zhangpei Chen ◽  
...  
Keyword(s):  
Magnetic Particles ◽  
Dibutyl Phthalate ◽  
Degradation Process ◽  
Environmental Safety ◽  
Degradation Efficiency ◽  
Precipitation Method ◽  
Solution Ph ◽  
Fluorescent Lamps ◽  
Butyl Phthalate ◽  
Co Precipitation

Abstract In recent years, industrial contaminants and especially organic pollutions have been threatening both environmental safety and human health. Particularly, dibutyl phthalate (DBP) has been considered as one of the major hazardous contaminants due to its widespread production and ecological toxicities. Consequently, reliable methods toward the efficient and environmentally benign degradation of DBP in wastewater would be very desirable. To this end, a novel magnetically separable porous TiO2/Ag composite photocatalyst with magnetic Fe3O4 particles as the core was developed and successfully introduced to the photocatalytic degradation of DBP under visible irradiation with a fluorescent lamp. The presented work describes the grafting of Ag co-doped TiO2 composite on the silica-modified porous Fe3O4 magnetic particles with a simple and inexpensive chemical co-precipitation method. Through the investigation of the influencing factors including photocatalyst dosage, initial concentration of DBP, solution pH, and H2O2 content, we found that the degradation efficiency could reach 74%. The photodegradation recovery experiment showed that the degradation efficiency of this photocatalyst remained almost the same after five times of reuse. In addition, a plausible degradation process was also proposed involving the attack of active hydroxyl radicals generated from this photocatalysis system and production of the corresponding intermediates of butyl phthalate, diethyl phthalate, dipropyl phthalate, methyl benzoate, and benzoic acid.

scholarly journals Strength of Humic Acid Aggregates: Effects of Divalent Cations and Solution pH

ACS Omega ◽  
2019 ◽  
Vol 4 (5) ◽  
pp. 8559-8567 ◽  
Author(s):  
Azizul Hakim ◽  
Tomoharu Suzuki ◽  
Motoyoshi Kobayashi
Keyword(s):  
Humic Acid ◽  
Divalent Cations ◽  
Solution Ph

Advanced oxidation of methyl tert-butyl ether (MTBE) by UV/TiO2 and H2O2-UV/TiO2 processes

2006 ◽  
Vol 6 (2) ◽  
pp. 77-85 ◽  
Author(s):  
C.-H. Hung
Keyword(s):  
Light Intensity ◽  
Degradation Rate ◽  
Reaction Rate ◽  
Experimental Results ◽  
Methyl Tert Butyl Ether ◽  
H2o2 Concentration ◽  
Pseudo First Order Reaction ◽  
Butyl Ether ◽  
Solution Ph ◽  
Degradation Rates

This study investigated photocatalysis of MTBE via both UV/TiO2 and H2O2-UV/TiO2 processes. Several experimental parameters including pH level, H2O2 concentration, TiO2 dosage and light intensity were investigated. The experimental results demonstrated the degradation of MTBE following a pseudo first-order reaction in both reaction systems. Faster degradation rates were observed in alkaline solution for the UV/TiO2 system, but for the H2O2-UV/TiO2 system, faster degradation rates were detected in acidic solution. More dosage of TiO2 and irradiated light intensity were beneficial for the photocatalysis of MTBE. However, a peak reaction rate was observed at a TiO2 concentration of about 500 mg/L. The experimental results also indicated that the degradation rate of MTBE was enhanced by the addition of H2O2. H2O2 could be a more efficient electron acceptor than oxygen for retarding recombination of electron–hole pairs. The degradation rate in the H2O2-UV/TiO2 system was about 2.8 times faster than that in the UV/TiO2 system for solution pH below 5, and the rate increased 30% for solution pH above 6. In addition, it is observed that the reaction rate of MTBE increased quickly with H2O2 concentration at low H2O2 dosages, but the rate was independent of H2O2 dosage when adding too much H2O2.

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