Low Molecular Weight Acids Research Articles

Copurification of chicken liver soluble thiamine monophosphatase and low molecular weight acid phosphatase

Copurification of chicken liver soluble thiamine monophosphatase and low molecular weight acid phosphatase

Investigations on reclaimed oil performance through measurement of the relative free radical content

The accelerated thermal ageing process was organized to compare the performance of oils before and after being subjected to oil reclamation. New mineral oil of the same brand was used as a base line measurement for evaluating the performance of the reclaimed oil with and without inhibitor. Samples consisting of oil, paper and metallic catalysts including zinc, copper, aluminum, and iron were aged at 115 °C in an air circulating oven for 250, 500 and 750 hours. A free radical reagent, 2.2 diphenyl-1-picrylhydrazyl (DPPH), was used to determine the relative concentration of free radicals in the oil samples. Key ageing indicators, namely free radical scavenging activity (RSA), relative content of dissolved decay products (DDP), turbidity, total acid number (TAN), interfacial tension (IFT), dielectric dissipation factor (DDF), and absolute water content for oil, and low molecular weight acids (LMA), and tensile index (TI) for paper, were measured regularly. It was found that the performance of the reclaimed oil is definitely better than the non-reclaimed oil, and is highly likely competitive with new mineral oil with the same brand. The results show that after a long run of the ageing process, RSA and DDP of the reclaimed oil without inhibitor are respectively more and less than that of the new oil. In addition, slower reduction of TI of paper aged in the reclaimed oils corroborates the theory that the paper degradation in a transformer can be reduced through oil reclamation.

Enhanced sludge solubilization and dewaterability by synergistic effects of nitrite and freezing

In this study, nitrite was added into sludge during freezing process to evaluate its role in waste activated sludge (WAS) solubilization and effect on sludge dewatering characteristics. The results showed that the introduction of 100 mg L−1 of nitrite could increase dissolved organic carbon (DOC) concentration from 29.5 to 48.8 mg DOC g−1 VSS under freezing conditions. More DOC was released with the increase of nitrite concentration. Freezing temperature, or freezing speed, also played a role in sludge solubilization. It was found that some readily-biodegradable low molecular weight (LMW) compounds, e.g. LMW protein, LMW polysaccharide, LMW neutrals, building blocks and LMW acids, were mainly released during the freezing process with the presence of nitrite. Interestingly, nitrite could also improve the sludge filterability at the lower nitrite concentration as a result of the increased sludge particle size. However, electrolytes (sodium nitrite) addition effects may mask such enhancement when nitrite concentration was high (800 mg L−1). The rheological characteristics of sludge could be well modeled by Herchel-Bulkley model and the introduction of nitrite into freezing process further increased sludge flowability and decreased sludge viscosity. These results indicated that freezing with the presence of suitable concentration of nitrite could promote sludge solubilization and dewaterability. As such, good liquid and solid separation can be achieved with the recovery of liquid stream as carbon source.

Intramolecular deactivation processes of electronically excited Lanthanide(III) complexes with organic acids of low molecular weight

The luminescence of Lanthanide(III) complexes with different model ligands was studied under direct as well as sensitized excitation conditions. The research was performed in the context of studies dealing with deep-underground storages for high-level nuclear waste. Here, Lanthanide(III) ions served as natural analogues for Actinide(III) ions and the low-molecular weight organic ligands are present in clay minerals and furthermore, they were employed as proxies for building blocks of humic substances, which are important complexing molecules in the natural environment, e.g., in the far field of a repository site. Time-resolved luminescence spectroscopy was applied for a detailed characterization of Eu(III), Tb(III), Sm(III) and Dy(III) complexes in aqueous solutions. Based on the observed luminescence the ligands were tentatively divided into two groups (A, B). The luminescence of Lanthanide(III) complexes of group A was mainly influenced by an energy transfer to OH-vibrations. Lanthanide(III) complexes of group B showed ligand-related luminescence quenching, which was further investigated. To gain more information on the underlying quenching processes of group A and B ligands, measurements at different temperatures (77K≤T≤353K) were performed and activation energies were determined based on an Arrhenius analysis. Moreover, the influence of the ionic strength between 0M≤I≤4M on the Lanthanide(III) luminescence was monitored for different complexes, in order to evaluate the influence of specific conditions encountered in host rocks foreseen as potential repository sites.

Viscossuplementação intra‐articular de ácidos hialurônicos em modelo experimental de osteoartrite

ObjectiveTo analyze, from the immunohistochemical perspective, the effects of hyaluronic acid of different molecular weights in an experimental model of osteoarthritis in rabbits. MethodsForty‐four male California rabbits were randomly assigned to three different groups (PR, S, and P) and submitted to the resection of the anterior cruciate ligament of the right knee. Three weeks after the surgical procedure, three intra‐articular weekly injections were carried out with low‐molecular‐weight native hyaluronic acid (Hyalgan®) to PR group, high molecular weight branched chain hyaluronic acid (Synvisc®) to group S, and saline solution 0.9% to group P. All animals were sacrificed 12 weeks after the surgical procedure, and the tibial plateaus of the infiltrated knees were then dissected. Histological sections of cartilage from the tibial plateau support areas were stained with immunohistochemical markers in order to investigate the amount of metalloproteases (MMPs 3 and 13) and their inhibitors (TIMPs 1 and 3). The staining intensity was quantified on a Zeiss Imager.Z2 Metasystems microscope and analyzed by Metafer4 Msearch software. ResultsThe chondroprotective effect of the hyaluronic acids used in the study was demonstrated when compared to the control group. However, the comparison between them presented no significant statistical difference regarding chondroprotection. ConclusionThe injection of saline solution demonstrated signs of OA development, while adding native hyaluronic acid of low molecular weight (Hyalgan®) and hyaluronic acid of high molecular weight (Synvisc®) protected the articular cartilage in this model of OA.

Environmental geochemistry significance of organic phosphorus: An insight from its adsorption on iron oxides

Iron oxides in suspended particulate matter or bottom sediments can remove P from natural waters via sorption, rendering it unavailable for biological uptake. In this work, three dissolved OP compounds, were selected as adsorbents to investigate their adsorption behavior on two typical iron oxides. The results showed that the formation of nonprotonated and protonated bidentate complexes were the dominant mechanisms in the initial stage (∼10 min) and the following stage (10–1440 min) during the adsorption process, respectively, in which the formation of protonated bidentate complex is the dominant mechanism in the whole adsorption process. Moreover, the adsorption density of P compounds on iron minerals increased with the temperature increase, indicating the endothermic and spontaneous of the adsorption process; pH presented negative effects on the adsorption of P-compounds on both hematite and goethite. Low molecular weight acid (LMWOAs) suppressed the adsorption of P compounds and the inhibitory effects increased with the number of carboxyl groups and the molecular size increasing. On the basis of this work, it can be deduced that P level will be largely elevated in water column from the WLSH-like lakes due to that the alkalization of water, the flourish of macrophyte and the icebound effects presented negative effects on P adsorption towards Fe oxyhydroxides in sediments. This work helps to interpret the knowledge linkage regarding the factors driving OP compounds behavior and bioavailability in lake ecosystem.

Equilibrium partitioning of naphthenic acids and bases and their consequences on interfacial properties

This article aims to create a model to accurately predict the equilibrium partitioning of naphthenic acids and basic crude oil components between the oil and water phase. The model was tested on 2 acids and 2 bases. After a review of the properties of crude oil acids and bases, the equilibrium partitioning of acids and bases with different molecular weight was analyzed over a pH interval using heptane as the oil phase and 3.5wt.% NaCl as the water phase. Phenylacetic acid would represent the low molecular weight acid while 4-heptylbenzoic acid was chosen to represent the high molecular weight one. Likewise, 4-ethylaniline and 4-decylaniline were chosen as corresponding bases. The partitioning of the two acids and the low molecular weight base was successfully modelled by considering the acid dissociation constant pKa in aqueous phase and the partition ratio Pwo of the non-ionized species between oil and aqueous phase. The high molecular weight base did not significantly partition into the aqueous phase at the pH range studied. The results show that acid species are more water soluble than basic species of similar molecular weight. In presence of calcium the partitioning of acids is successfully modelled by accounting for the precipitation of naphthenate soap with a solubility constant Ks. The kinetic interfacial tension between heptane and 3.5% NaCl aqueous buffer was also analyzed with oils that contained single compounds, two bases, two acids and all four components over a pH interval to identify any interfacial acid-base interactions. No significant interfacial interaction could be identified, mostly due to similar pKa values.

Biologically active ion exchange (BIEX) for NOM removal and membrane fouling prevention

The natural organic matter (NOM) removal efficiency and regeneration behavior of ion-exchange filters with promoted biological activity (BIEX) was compared to operation where biological activity was suppressed (i.e. abiotic conditions). The impact of BIEX pre-treatment on fouling in subsequent ultrafiltration was also investigated. Biological operation enhanced NOM removal by approximately 50% due to an additional degradation of smaller humic substances, building blocks and low molecular weight acids. Promotion of biological activity significantly increased the time to breakthrough of the filters and, therefore, is expected to lower the regeneration frequency as well as the amount of regenerate of which to dispose. Pre-treatment using BIEX filters resulted in a significant decrease in total and irreversible fouling during subsequent ultrafiltration. The decrease was attributed to the effective removal of medium and low molecular weight NOM fractions. The results indicate that BIEX filtration is a robust, affordable and easy-to-operate pre-treatment approach to minimize fouling in ultrafiltration systems and enhance the quality of the produced permeate.

Mechanism analysis of powdered activated carbon controlling microfiltration membrane fouling in surface water treatment

The mechanism of powdered activated carbon (PAC) mitigating microfiltration (MF) membrane fouling for surface water treatment was investigated via blocking models, resin adsorption fractionation, high performance size exclusion chromatography (HPSEC) with peak-fitting, and interaction free energy theory. The results identified cake formation as the major mechanism of membrane fouling. Also, PAC pre-treated water showed a relatively lower fouling rate than untreated raw water and PAC had a positive effect on improving membrane flux on account of the enhanced removal of neutral hydrophilic compounds (NEU) and strongly hydrophobic acids (SHA) (based on fractionation), and building blocks and low molecular weight acids (BB&LMW-A) (based on HPSEC). Analysis of the interfacial energy between membrane and foulants via the extended Derjaguin–Landau–Verwey–Overbeek (XDLVO) theory found that AB interaction energy played a dominating role in the components of interaction free energies during MF process. PAC, by decreasing AB interaction energy, could thus control membrane fouling.

Influence of drill mud on the microbial communities of sandstone rocks and well fluids at the Ketzin pilot site for CO2 storage

At a pilot site for CO2 storage in Ketzin (Germany), a drastic decrease in injectivity occurred in a well intended for injection. This was attributed to an obstruction of the pore throats due to microbial degradation of the organic drill mud and subsequent iron sulfide (FeS) precipitation in the highly saline brine (240 g L−1). To better understand the biogeochemical processes, the response of the autochthonous microbial community to drill mud exposure was investigated. Pristine cores of two aquifers with different salinity were incubated under simulated in situ conditions (50 bar, 40 °C and 45 bar, 25 °C, respectively) and CO2 atmosphere. For the first time, rock cores obtained from the CO2 plume of the storage formation were investigated. The influence of acetate as a biodegradation product of drill mud polymers and the effectiveness of a biocide were additionally tested. Increased microbial diversities were observed in all long-term (8–20 weeks) incubations, even including biocide. Biofilm-like structures and small round-shaped minerals of probable microbiological origin were found. The results indicate that the microbial community remains viable after long-term CO2 exposure. Microorganisms hydrolyzing cellulose polymers (e.g., Burkholderia spp., Variovorax spp.) biodegraded organic components of the drill mud and most likely produced low molecular weight acids. Although the effects of drill mud were less strong as observed in situ, it was demonstrated that acetate supports the growth of sulfate-reducing bacteria (i.e., Desulfotomaculum spp.). The microbial-induced precipitation of amorphous FeS reduced the injectivity in the near-well area. Therefore, when using organic drill mud, the well must be cleaned intensively to minimize the hazards of bacterial stimulation.

Fouling behaviors correlating to water characteristics during the ultrafiltration of micro-polluted water with and without the addition of powdered activated carbon

The aim of this paper was to investigate the effects of powdered activated carbon (PAC) pretreatment on the fouling behavior of an ultrafiltration (UF) membrane during micro-polluted water treatment. The results of this study demonstrated that PAC had a positive influence on fouling mitigation. Specifically, PAC-pretreated water had lower fouling resistances (FRs) and fouling indexes (FIs) than raw water. Liquid chromatography combined with peak-fitting analyses of raw water with and without PAC pretreatment suggested that PAC adsorption was much effective in reducing the contents of the low molecular weight acids and building blocks (LMWA&BB) and the humic substance (HS) fractions in raw water. Principal component analysis (PCA) was also used to identify the fouling behaviors associated with the characteristics of the water samples. Significant correlations (r2) of LMWA&BB with hydraulic reversible resistance (Rre), hydraulic irreversible resistance (Rir), total fouling index (TFI) and the hydraulically irreversible index (HIFI) were found (0.7534, 0.8430, 0.6297 and 0.7015, respectively), indicating that LMWA&BB contributed more significantly than biopolymers(BP) and HS to membrane fouling. The likely mechanism by which the PAC alleviated fouling was the reduction of the LMWA&BB fraction’s presence at the membrane surface and pores. These results suggest that the application of the PAC pretreatment preceding passage through the UF membrane is a promising approach for membrane fouling mitigation.

Optimizing Hollow Fibre Nanofiltration for Organic Matter Rich Lake Water

Over the years, various technologies have been utilized for Natural Organic Matter (NOM) removal with varying degrees of success. Conventional treatment methods comprising of coagulation, flocculation, sedimentation, or filtration are widely used to remove NOM. An alternative to these conventional methods is to use spiral wound membranes. These membranes tend to remove too much hardness whilst being ineffective in disinfection. They also have a low tolerance to chlorine and thus, have limited chemical cleaning options. In this study, we investigated how an alternative and new innovative filtration concept, based on capillary NF membranes from modified polyethersulfone (PES), may be used to treat soft but humus-rich surface waters. Comprehensive performance tests, with a fully automated membrane pilot equipped with a full-scale sized test module (40 m2 membrane surface), were conducted at WTP Görvälnverket, which is operated by the water utility Norrvatten, providing drinking water from Mälaren (SUVA = 2.7–3.3, TOC = 7.0–10.0 mg·L−1) for about 500,000 people in the northern part of the Swedish capital of Stockholm. The removal of both UV and DOC was modeled using a solution diffusion approach. The optimized parameters allow deducing optimal operation conditions with respect to energy, water consumption, and permeate water quality. Optimal cross flow velocity was determined to be 0.75 m·s−1 at 80% recovery and a flux of 12–18 L·m−2·h−1. Under these conditions, 80% of the UV, 75% of the Humic Substances (MW = 600) and 70% of TOC were removed (from 8 to below 2 mg·L−1). A higher cross flow velocity led to marginal improvement (+2%) while both higher and lower membrane fluxes degraded permeate water quality. Apparent optimized diffusion coefficients for UV and TOC were around 1.2–2.4 × 10−10·m2·s−1 and were similar to values found in the literature. Due to their higher diffusion coefficients and higher permeability coefficient, only 40% of the low molecular weight acids (MW = 300–400) were retained. Approximately 30%–40% of the low molecular weight acids in the permeate can be further removed using GAC post NF. The resulting energy consumption of a hypothetical four-stage design, at average operating temperature of 5.73 °C, was calculated to be around 0.6 kWh·m−3 produced water.

ПОКАЗНИКИ ПЕРОКСИДНОГО ОКИСНЕННЯ ЛІПІДІВ У КРОВІ ВІВЦЕМАТОК, ХВОРИХ НА ГЕПАТОДИСТРОФІЮ

The article deals with the results of studies on the causes and clinical manifestations of hepatodystrophy in ewes, indicators status of lipid peroxidation – TBA-active products, lipid hydroperoxides, diene conjugates.In order to establish the causes of hepatodystrophy in sheep, we have analyzed the feed rations. Sheep investigated 24 local breeds aged 3 – 4 years, weighing 45 – 56 kg. Conducted clinical study animals and blood were collected for laboratory analysis. Serum sheep determined the content of malondialdehyde (MDA-active products) using thiobarbituric acid (Stalnaja I.D., Haryshvyly T.G, 1977) and lipid hydroperoxides using ammonium thiocyanate (Romanova LA, Stalnaja I.D., 1977). In blood examined diene conjugates (Stalnaja I.D., 1977).High performance is ensured animals by creating appropriate technical conditions and feeding. Violation of maintenance processes and non-biological nutrition of the cause performance degradation, the spread of disease and culling of animals. Development hepatodystrophy animals observed in animals fed low-quality forage and depraved that contain a number of toxic products of oxidation of fats – aldehydes, ketones, low molecular weight acids, hydroxy acids, which have toxic properties and also due to an unbalanced diet for the main nutrients and biologically active substancesThe main causes of primary hepatodystrophy in sheep is imbalanced nutrition and lack of essential nutrients in the diet. In analyzing the diet of established lack of dry matter, raw protein, digestible protein, raw fiber, sugar and starch. Value sugar and starch with digestible protein accounted for 1,78: 1, and sugar-protein ratio – 0,77. Rations were scarce for vitamins D and E, microelements – Sulphur, copper, zinc, cobalt and iodine.In ewes suffering from hepatodystrophy was set the development of oxidative stress – increase in blood activity of TBA-active products, lipid hydroperoxides, diene conjugates. In particular, concentration of diene conjugates was increased by twice the number of hydroperoxides lipids was increased by three times and the activity of TBA-active products was increased by five times compared with clinically healthy animals. Histological examination of liver biopsies of ewes was set that the develop of protein granular and fatty degeneration of hepatocytes.

Hydrophobic interaction and patch charge attraction in α-Al2O3 dispersions under the influence of adsorbed low molecular-weight polyacrylic acid sodium salt and poly(methacrylic acid) sodium salt: yield stress and AFM force study

Maximum yield stress data showed that low molecular-weight (Mw) (∼7 kDa) poly(methacrylic acid) sodium salt (PMA-Na) additive at low surface coverage displayed significant patch charge attraction in contrast to polyacrylic acid sodium salt (PAA-Na) additive of similar Mw and surface coverage. Intramolecular hydrophobic interaction between CH3 groups in the polymer molecule during adsorption produced a much more compact patch with a higher negative charge density giving rise to the stronger patch charge attraction. At high surface coverage, intermolecular hydrophobic interaction between CH3 groups on the adsorbed layer of the interacting particles was not observed from maximum yield stress data. Such interaction was, however, observed in AFM force-distance characterization data for interaction between spherical alumina particles and sapphire plates coated with PMA-Na in retraction mode. The compression of the adsorbed layers at contact during the approach mode was postulated to deform and breakup the intramolecular interaction between the CH3 groups and promoted intermolecular interaction between these groups in the layer coating the particle and plate. This resulted in a strong adhesion force seen in the retraction mode after contact at low pH near the point of zero charge.

Kinetics of natural organic matter (NOM) removal during drinking water biofiltration using different NOM characterization approaches

To better understand biofiltration, concentration profiles of various natural organic matter (NOM) components throughout a pilot-scale drinking water biofilter were investigated using liquid chromatography – organic carbon detection (LC-OCD) and fluorescence excitation and emission matrices (FEEM). Over a 2 month period, water samples were collected from six ports at different biofilter media depths. Results showed substantial removal of biopolymers (i.e. high molecular weight (MW) NOM components as characterized by LC-OCD) and FEEM protein-like materials, but low removal of humic substances, building blocks and low MW neutrals and low MW acids. For the first time, relative biodegradability of different NOM components characterized by LC-OCD and FEEM approaches were investigated across the entire MW range and for different fluorophore compositions, in addition to establishing the biodegradation kinetics. The removal kinetics for FEEM protein-like materials were different than for the LC-OCD-based biopolymers, illustrating the complementary nature of the LC-OCD and FEEM approaches. LC-OCD biopolymers (both organic carbon and organic nitrogen) and FEEM protein-like materials were shown to follow either first or second order biodegradation kinetics. Due to the low percent removal and small number of data points, the performance of three kinetic models was not distinguishable for humic substances. Pre-filtration of samples for FEEM analyses affected the removal behaviours and/or kinetics especially of protein-like materials which was attributed to the removal of the colloidal/particulate materials.

Organic micropollutant removal from groundwater: comparison of pellet softening and nanofiltration

This study investigated the fate of selected pharmaceuticals and estrogens and the characteristics of bulk organic matter during pellet softening and proposed a possible hybridization with nanofiltration (NF) treatment. A groundwater softening system called pellet softening was used to remove calcium ions from groundwater by crystallizing calcium carbonate on the surface of sand grains that were used as seeding material. This crystallization was confirmed by X-ray powder diffraction, and X-ray fluorescence and scanning electron micrographs were used to characterize the surface of the sand grains during pellet softening. The fluorescence excitation–emission matrix showed that humic-like substances were slightly removed and that specific UV absorbance values decreased after pellet softening. The humic fraction determined by liquid chromatography-organic carbon detection was slightly more attenuated than the fractions of biopolymers, building blocks, low molecular weight acids, and low molecular weight neutrals. Therefore, the aromatic content per unit of dissolved organic carbon was preferentially attenuated during pellet softening. The average removal efficiencies of the three estrogens and 12 selected pharmaceuticals during the softening process were 59 and 5.7%, respectively. However, there was a greater reduction of pharmaceuticals during NF.

Palladium and copper catalyzed Sonogashira decarboxylative coupling of aryl iodides and alkynyl carboxylic acids

A mild procedure of palladium and copper catalyzed decarboxylative cross-coupling reaction of aryl halides and alkynyl carboxylic acids has been developed. Low molecular weight acids, to introduce small building blocks, were specifically used. This methodology is easy to implement and uses common reactants and catalysts.

Evaluation of organic matter characteristics of FO and RO concentrates

AbstractNumerous studies on forward osmosis (FO) have been conducted to understand fouling mechanisms better, especially compared to the reverse osmosis (RO) process. In this study, characteristics of concentrates from FO and RO filtrations were investigated to evaluate the rejection mechanisms of organic matter and to elucidate the effects of pressure on the active membrane side and hydrophobicity of organic compounds in the feed solution. The fluorescence excitation–emission matrix (FEEM) and a liquid chromatography-online carbon detector were employed to analyze the properties of organic matter. Secondary wastewater effluent was used to compare the concentrates. More humic-like fractions of organic matter remained in the concentrate from the FO than the RO process. In the concentrate from RO, building blocks and low-molecular weight acid were noticeable. The pressurized filtration experiments of the FO membrane revealed that operation with transmembrane pressure produced similar properties of the conce...

Granular activated carbon adsorption of organic micro-pollutants in drinking water and treated wastewater – Aligning breakthrough curves and capacities

Small-scale granular activated carbon (GAC) tests for the adsorption of organic micro-pollutants (OMP) were conducted with drinking water and wastewater treatment plant (WWTP) effluent. In both waters, three influent OMP concentration levels were tested. As long as the influent OMP concentrations are below certain thresholds, the relative breakthrough behavior is not impacted in the respective water. Accordingly, the GAC capacity for OMP is directly proportional to the influent OMP concentration in the corresponding water. The differences between the OMP breakthrough curves in drinking water and WWTP effluent can be attributed to the concentrations of the low molecular weight acid and neutral (LMW) organics of the waters. Presenting the relative OMP concentrations (c/c0) over the specific throughput of the LMW organics (mg LMW organics/g GAC), the OMP breakthrough curves in drinking water and WWTP effluent superimpose each other. This superimposition can be further increased if the UV absorbance at 254 nm (UV254) of the LMW organics is considered. In contrast, using the specific throughput of the dissolved organic carbon (DOC) did not suffice to obtain superimposed breakthrough curves. Thus, the LMW organics are the major water constituent impacting OMP adsorption onto GAC. The results demonstrate that knowing the influent OMP and LMW organics concentrations (and UV254) of different waters, the OMP breakthroughs and GAC capacities corresponding to any water can be applied to all other waters.

Novel Magnetically Separable Reduced Graphene Oxide (RGO)/ZnFe2O4/Ag3PO4 Nanocomposites for Enhanced Photocatalytic Performance toward 2,4-Dichlorophenol under Visible Light

Novel magnetically separable nanocomposite photocatalyst reduced graphene oxide (RGO)/ZnFe2O4/Ag3PO4, prepared by the solvothermal and in situ precipitation method, was first investigated as the photocatalyst for 2,4-dichlorophenol (2,4-DCP) degradation under visible light irradiation. The catalysts with different mass ratios were systematically characterized with FT-IR, XPS, XRD, SEM, FESEM, UV–vis, and PL. The nanocomposite RGO/ZnFe2O4/Ag3PO4 showed enhanced photocatalytic activity and stability compared with pure Ag3PO4 under the same conditions. During the photocatalysis process, intermediates of 4-chlorophenol (4-CP) and some other low molecular weight acids, including maleic acid, glyoxylic acid, glycolic acid, oxalic acid, acetic acid, and formic acid were detected through GC/MS. According to these analyses and the capture experiments of reactive species, the photocatalytic mechanism of RGO/ZnFe2O4/Ag3PO4 was discussed on the basis of the heterojunction energy-band theory and Z-scheme theory, and a possible degradation pathway of 2,4-DCP was also proposed.