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In order to expand the application range of surfactants, octadecyl trimethyl ammonium chloride (OTAC) and polyacrylic acid (PAA) were used as raw materials to synthesize octadecyl trimethyl ammonium polyacrylic (OTAP). The molar ratios of OTAC to polyacrylic acid monomer were 1:1, 1:2 and 1:3. The synthesized compounds were named as OTAP-1, OTAP-2, OTAP-3. The obtained research results show that the best foaming ability was achieved with OTAP-1, and the best foam stability with OTAP-2. When the concentration was 2.0 g/L, the order of the emulsifying ability was: OTAP-1 > OTAP-2 > OTAP-3; when the concentration was 4.0 g/L, the emulsifying ability order was OTAP-2 > OTAP-3 > OTAP-1. OTAP-1 had a corrosion inhibition capacity of up to 85.11 %, and OTAP-2 and OTAP-3 had a sustained release rate of 81.06 % and 72.82 %, respectively. OTAP-3 had a good effect on scale inhibition, and the scale inhibition rate was 65.01 %.

A novel Mg-Al metal oxide has been successfully synthesized by the calcination of hierarchical porous Mg-Al hydrotalcite clay obtained by using filter paper as a template under hydrothermal conditions. Various characterizations of the obtained nanoscale oxide particles verified the uniform dispersion of Mg-Al metal oxides on the filter paper fiber, which had a size of 2–20 nm and a highest specific surface area (SSA) of 178.84 m2/g. Structural characterization revealed that the as-prepared Mg-Al metal oxides preserved the tubular morphology of the filter paper fibers. Further experiments showed that the as-synthesized Mg-Al metal oxides, present at concentrations of 0.3 g/L, could efficiently remove sulfonated lignite from oilfield wastewater (initial concentration of 200 mg/L) in a neutral environment (pH = 7) at a temperature of 298 K. An investigation of the reaction kinetics found that the adsorption process of sulfonated lignite (SL) on biomorphic Mg-Al metal oxides fits a Langmuir adsorption model and pseudo-second-order rate equation. Thermodynamic calculations propose that the adsorption of sulfonated lignite was spontaneous, endothermic, and a thermodynamically feasible process.

Sludge-based adsorbent (S-AB) converted by oily sludge can make full use of the precious resource. In this paper, oily sludge and discarded sawdust are used to prepare adsorbent through chemical activation. The adsorbent prepared is used to adsorb raw petroleum. Firstly, the most reasonable chemical activator ZnCl

Cationic quaternary ammonium surfactant s are widely applied in many fields, such as detergent, cosmetics, petroleum and natural gas industries. However, the study of the effect of anion on cationic surfactants is rare. To research the influence of anions on the surface properties, a cationic surfactant was prepared, (cetyltrimethyl ammonium isonicotinate, CTAIN), and the surface properties were studied, including surface tension, critical micelle concentration, foaming ability and stability, and corrosion inhibition. The results indicated that the minimum surface tension of CTAIN is lower than that of CTAC, the foaming ability and foaming stability of CTAIN is higher than that of CTAC, and the corrosion inhibition efficiency on mild steel of CTAC is more potent than that of CTAIN. All the results indicate that the new cationic quaternary ammonium surfactant is a useful surfactant in the related fields.

In this work, Span 60 and Span 80, two representatives of nonionic surfactants, were evaluated as clean flow improvers for crude oil. The results show that both of these two nonionic surfactants can improve the flow properties of crude oil samples, especially the Span 80. In a certain condition, maximum viscosity reduction ratio of crude oil with Span 80 was up to 70.0% and the maximum pour points decrease was 9.0°C. DSC thermograms and microphotographs discover the co-crystallization of Span 80 and saturated hydrocarbon component of the crude oil, which causes the wax crystal accumulation not closely and reduces the wax peak temperature and wax precipitation point of crude oil. Combined with the steady conformations analysis, mechanism of Span surfactants as clean flow improvers for crude oil was further discussed. Due to the cis-double bonds in Span 80 and crystal form transition of wax crystal growth with Span 80, Span 80 was superior to Span 60 as flow improvers for crude oil.

Quaternary ammonium cationic surfactants are widely applied in many different fields, such as textile, cosmetic, and petrochemical industries. However, little research has been done on the effects of anion on cationic surfactants. In this study, two new surfactants, cetyltrimethylammonium glycine (CTAG) and octadecyltrimethylammonium glycine (OTAG), were prepared in a simple way using cetyltrimethylammonium chloride (CTAC), octadecyltrimethylammonium chloride (OTAC), and glycine. Then the surface activities were evaluated and compared with the two raw materials. The surface activity of CTAG and OTAG, including surface tension, foaming ability, and emulsification, is better than that of CTAC and OTAC in each case. With the glycine, the corrosion inhibition efficiencies of CTAG and OTAG are 91.12% and 97.89%, respectively, which are more effective than that of CTAC and OTAC. The superior performance of the two surfactants will be very helpful for developing an effective solution in the future.

The clay with high oil content form soil lumps, which is hard for microbes to repair. In this paper, the bioremediation + biostimulation was applied to improve the bioremediation effect of the soil with high oil content, that modified by local cow dung and sandy soil, the ecological toxicity of the soil after restoration was further analyzed. After 53 days of bioremediation, the degradation efficiency with respect to the total petroleum hydrocarbon (TPH) content reached 76.9% ± 2.2%; the soil bacterial content reached 4.9 × 107 CFU/g soil and the results were better than those in the natural attenuation M1group of experimental soils. The relative abundances of petroleum-degrading bacteria added to M5 remained high (Achromobacter 9.44%, Pseudomonas 31.06%, and Acinetobacter 14.11%), and the proportions of some other indigenous bacteria (Alcanivorax and Paenibacillus) also increased. The toxicity of the bioremediated soil was reduced by seed germination and earthworm survival experiments.

Acidified hydraulic fracturing technology is a technical measure that uses acid liquid to react with minerals in near wells or reservoirs to enhance permeability, oil well and shale gas extraction, and increase the injection volume of wells. After the acidification construction is completed, the residual acid liquid will be discharged to the ground, which forms acidified waste liquid with low pH and complex composition. Recent studies providing snapshots of processing technology on the acidified waste have highlighted the need to convert the high concentration of Fe(II) in the acidified wastewater into flocculating components through advanced oxidation process. Here we report the discovery of the oxidation kinetics of ferrous ion in simulated acidified waste system, which based on the analysis of major pollutants and high iron content. We show that the change of concentration of ferrous ions was determined by chemiluminescence in tandem with flow injection, and the reaction of hydrogen peroxide with Fe(II) is a pseudo-first-order reaction. The reaction rate constants at Fe(II) of 50, 100 and 150 mg/L are 0.12612, 0.41686, 1.18230 s−1 respectively. In addition, we evaluated the adaptability of the catalytic oxidation system to acidified waste liquid. This offers a theoretical basis for treatment of acid hydraulic fracturing flowback and a series of treatability of tests, which serves to guide the selection of suitable treatment approach.

We report a novel nanophotosensitizer via one-step covalent assembly of dopamine and genipin. This is the first report unveiling the photodynamic effect of dopamine-based materials. These nanophotosensitizers can also act as pH-responsive drug nanocarriers via a catechol-boronate linkage, thus achieving combined PDT and chemotherapy for highly efficient cancer treatment.

Hydroxypropyl guar gum (HPGG), polyacrylamide (PAM) and carboxymethyl cellulose (CMC) are widely used as thickeners in fracturing fluids, and thus contaminate wastewater. We designed a clean oxidation process for the treatment of waste fracturing fluids containing hydroxypropyl guar gum and other polymers under high pH value. For that, 1,10-phenanthroline(L)-transition metal complexes were prepared and screened for viscosity reduction of hydroxypropyl guar gum oxidized by hydrogen peroxide (H2O2). Results show that Cu(II)L exhibited high catalytic performance for the degradation of hydroxypropyl guar gum in a pH range of 7–14. Under the optimum experimental conditions, the viscosity of hydroxypropyl guar gum solution can be reduced effectively with 10.0% H2O2 and 5.0% Cu(II)L. The chemical oxygen demand (COD) of the hydroxypropyl guar gum solution decreased from 8 g/L to 65 mg/L. Cu(II)L also showed a high catalytic ability for the degradation of various polymers.

A series of complex was synthesized using phenyl hydroxamic acid and metallic chloride, and used for catalytic aquathermolysis of heavy oil at low temperatures for the first time. The effects of water content and catalyst concentration on aquathermolysis were investigated. And then a tri-component coupling aquathermolysis of water-heavy oil-methanol was designed and the reaction conditions were investigated. With the catalyst and methanol, the reaction occurred at temperatures as low as 180°C. The viscosity of the product was also substantially reduced by the decomposition of the large hydrocarbon molecules.

Cetyl trimethyl ammonium chloride (CTAC), cetyl trimethyl ammonium bromide (CTAB), and octadecyl trimethylammonium chloride (OTAC) were evaluated as clean flow improvers for crude oil. The results showed that all of them have some effect on the viscosity of crude oil in a certain temperature range, and can depress the pour point, among which CTAC is the most potent one. The viscosity was reduced to below 540 mPa s under different concentration at 35 °C by CTAC, and it can depress the pour points by 7.5 °C with the concentration of 0.03%. DSC analysis and microscopic morphology analysis discovered the interaction of CTAC and saturated hydrocarbon component of the crude oil, which can reduce the wax peak temperature and wax precipitation point of crude oil. CTAC may precipitate and pack with the long-chain alkane to form the crystal nucleus, while the cationic part and the corresponding Cl− anion can act as a wax crystal modifier and block the wax crystal to grow up, thereby reduce the risk to form three-dimensional networks.

A crude oil containing high paraffin from Yanchang Oilfield was studied for the situ waxing inhibition as an example in this work. The components were separated using silica gel column chromatography by different eluent and were named A1 to A14, and the characteristics of each component and their influence on wax crystallization were studied. It was found that the separated components could interact with each other to decrease the temperature of the wax point to 0.2–1.64 °C, but the effect on the amount of wax was relatively small. Polarized micrographs showed that the components also affect the morphology and distribution of the wax crystals. For example, the component A5 make the wax crystals of A1 larger and make the distribution of wax crystals in a certain direction and more dispersed.

A Zn(II) coordination complex was synthesized, characterized, and used for catalytic aquathermolysis of heavy oil at low temperatures for the first time. The effects of water content and catalyst concentration on aquathermolysis were investigated. And then a tri-component coupling aquathermolysis of waterheavy oil-methanol was designed and the reaction conditions were investigated. With the catalyst and methanol, the reaction occurred at temperatures as low as 180°C. The viscosity of the product was also substantially reduced from around 24 400 to 6420 mPa s by the decomposition of the large hydrocarbon molecules.

Co-precipitation of mineral-based salts during scaling remains poorly understood and thermodynamically undefined within the water industry. This study focuses on investigating calcium carbonate and calcium sulfate mixed precipitation in scaling. Scaling is often observed in the produced water supply as a result of treatment processes. Co-precipitation results were compared with experimental results of a single salt crystallization. Several parameters were carefully monitored, including the electrical conductivity, pH value, crystal morphology and crystal form. The existence of the calcium carbonate scale in the mixed system encourages the loose calcium sulfate scale to become more tightly packed. The mixed scale was firmly adhered to the beaker, and the adhesion of the co-deposition product was located between the pure calcium sulfate scale and the pure calcium carbonate scale. The crystalline form of calcium sulfate was gypsum in both pure material deposition and mixed deposition, while the calcium carbonate scale was stable in calcite form in the pure material deposition. In the co-deposition, apart from calcite form, some calcium carbonate scale crystals had metastable vaterite form. This indicated that the presence of SO42− ions reduced the energy barrier of the calcium carbonate scale and hindered its transformation from a vaterite form to a calcite one, and the increase in HCO3− content inhibited the formation of calcium sulfate scale.

Catalytic pyrolysis is a promising alternative for oil sludge disposal. There is significant development in pyrolytic catalysts of oil sludge in recent years, but there is no specific review about ...

Water injection is a common method for enhancing oil recovery in oilfield production processes. However, in the process of water injection development, the incompatibility between injected and formation water can easily cause formation pores and wellbore scaling problems, which compromise the oilfield production process. Considering a scaling well area in northern Shaanxi as example, scaling mechanism analysis and scale inhibition technology research were performed. The scale samples were subjected to water quality testing by total ion analysis and static compatibility experiment, in addition to scaling trend prediction and X-ray diffraction analysis. The calcium carbonate scale was found to be the main scale in this region and the main reasons for scale formation were: high content of CO32- and HCO3- in reinjection wastewater, high content of Ca2+ and Mg2+ in the produced water of the oil well, and poor compatibility between the formation water and reinjection wastewater. The formation of calcium carbonate scale was prevented by chemical scale inhibitor compounding and good chelation. Hence, the screened inhibitor showed good scale inhibitory effect and can provided technical support for the water injection process.

A series of Mannich base-transition metal coordination complex was synthesized and used for the catalytic aquathermolysis of heavy oil, among which we found that the Ni(II) complex is the most effective one. After reacted under a relative low temperature, 180°C, for 24 h, the viscosity of the heavy oil was decreased by 75.2% using 0.5 wt % Ni(II) complex. The results showed that the content of resin and asphaltenes was decreased, while the content of saturate and aromatic were increased after aquathermolysis reaction. Besides, the catalytic aquathermolysis could both decrease the viscosity of heavy oil, and reduce the content of heteroatoms, resulting in flow properties enhanced and the quality upgraded.

Pyrolysis is potentially an effective treatment of oily sludge for oil recovery, and the addition of a catalyst is expected to affect its pyrolysis behavior. In the present study, Fe/Al-pillared bentonite with various Fe/Al ratios as pyrolysis catalyst is prepared and characterized by XRD, N2adsorption, and NH3-TPD. The integration of Al and Fe in the bentonite interlayers to form pillared clay is evidenced by increase in the basal spacing. As a result, a critical ratio of Fe/Al exists in the Fe/Al-pillared bentonite catalytic pyrolysis for oil recovery from the sludge. The oil yield increases with respect to increase in Fe/Al ratio of catalysts, then decreases with further increasing of Fe/Al ratio. The optimum oil yield using 2.0 wt% of Fe/Al 0.5-pillared bentonite as catalyst attains to 52.46% compared to 29.23% without catalyst addition in the present study. In addition, the addition of Fe/Al-pillared bentonite catalyst also improves the quality of pyrolysis-produced oil and promotes the formation of CH4. Fe/Al-pillared bentonite provides acid center in the inner surface, which is beneficial to the cracking reaction of oil molecules in pyrolysis process. The present work implies that Fe/Al-pillared bentonite as addictive holds great potential in industrial pyrolysis of oily sludge.

A series of EDTA-metal complexes was prepared for the Fenton oxidation catalysts and Fe(II)L exhibits high catalytic performance for degradation of hydroxypropyl guar gum in a wide pH range 7.0–13.0. The viscosity of hydroxypropyl guar gum can be reduced with the 10.0% H2O2 and 5.0% Fe(II)L. The viscosity average molecular weight of hydroxypropyl guar gum was decreased from almost 2 million to 3,199. Most important of all, the chemical oxygen demand (COD) value can be decreased to 104 mg/L from 8,080 mg/L with enough H2O2, and Fe(II)L also shows great catalytic ability in the degradation of various polymers by H2O2. The proposed mechanism of the activation of H2O2 by the complex was studied.

Oily sludge is the production and collection of a mixture of oil and sludge produced during crude oil processing. It contains crude oil, heavy metals, organic toxins, and harmful substances. It is characterized by high water content, poor fluidity, and large volume. Recycling and disposal have always been important aspects of environmental protection in the petroleum industry. Therefore, the safe treatment of oily sludge is particularly important. Hydrothermal oxidation technology is an emerging technology in which the treatment of oily sludge is comprehensive and without secondary pollution. This article describes the basic principles and research progress of wet oxidation and supercritical water oxidation and focuses on the latest experimental research, advantages and disadvantages, and development prospects in the treatment of oily wastewater.

The catalytic degradation of organic wastewater by heterogeneous Fenton has attracted much attention in recent years. Compared with homogeneous Fenton, heterogeneous Fenton reaction has the advantages of wide pH range, low dissolved iron content after reaction, easy magnetic separation and good reusability. This paper mainly introduces the research progress of heterogeneous supported Fenton catalyst in the treatment of organic wastewater in recent years. In this paper, the degradation performance and recyclability of organic wastewater by catalysts are discussed, and the development direction of catalysts in the future is prospected.

Sludge treatment has become one of the most important challenges in environmental protection. With the improvement of sludge treatment standards, the environmentally-friendly and efficient pyrolysis technology developed has a good development prospect. The addition of catalyst is one of the important conditions affecting sludge pyrolysis. This paper introduces the influence of different kinds of catalysts on pyrolysis, and summarizes their advantages and disadvantages.

In view of the present situation of oily sludge pollution, the different treatment methods for oily sludge in different uses were briefly described. The composition and structure of oily sludge are affected by sludge type, source, pyrolysis conditions and subsequent treatment conditions, which lead to different treatment methods and treatment effects. At present, there is no unified standard for the treatment of oily sludge at home and abroad, which brings difficulties to the unified management of oily sludge treatment. Through the toxicity analysis of oily sludge and its residues, it is helpful to judge the harmfulness of oily sludge and its treatment residues, according to the harmfulness of oily sludge, effectively choose different follow-up treatment methods, it is beneficial to establish the scientific standard of oily sludge treatment. In this paper, the present post-treatment indexes of petroleum hydrocarbon content, heavy metal ion content, water content, Polycyclic aromatic hydrocarbon content and sulfur content in oily sludge are summarized.

The focus of the research is the minimizing amount of oil sludge via dehydration. The effects of using combination of polyaluminum chloride and biomass as additives on the possible improvement of the dehydration performance (evaluated via water content of oily sludge) of oil sludge and on the yield of pyrolysis oil at 723 K were investigated. The main influencing factors of dehydration considered in the experiment are biomass species and dosage, temperature, and flocculation time. The water content of oily sludge was significantly reduced when biomass ranging from 0.5 to 3.0 wt% on dosage ratio. The best phase dehydration performance was obtained from Apricot shell of 0.5 wt% at 313–323 K at flocculate time of 30–40 min, while the highest recovery percent of pyrolysis oil (33.54%) was obtained from Walnut shell of 1.0 wt%. The results indicate that the positive effects of the biomass in oily sludge on the improvement of dehydration performance and on recovery rate of the pyrolysis oil were observed. The m...

The research on the impacts of modified TiO2 nanoparticles (NPs) on interfacial tension (IFT) is in its infancy. Our work focuses on the IFT of the modified TiO2 and Gemini surfactant N,N,N′,N′-tetramethyl-N,N′-dimyristyl-1,2-ethane diammonium dichlone (YND1233) complex solutions for reservoir stimulation purposes. The factors of YND1233, modified TiO2 NPs, temperature, aging stability, adsorption loss, and mineralized degree were explored with the comparison of unmodified TiO2 NPs and YND1233 as contrast samples. The results indicate that the dynamic IFTs decrease and then increase with the concentrations of YND1233 and modified TiO2 NPs, and the minimum IFT appears at 0.200 and 0.010 wt%, respectively. YND1233/modified TiO2 complex solutions show lower and more stable IFTs, better temperature resistance, longer aging time, and lower adsorption on the surface of quartz sand. The modified TiO2 NPs and YND1233 in the YND1233/modified TiO2 complex solution can be adsorbed to the interface and decrease the I...

C17H12Cl2CuN6, monoclinic, P21/c (no. 14), a = 13.113(3) Å, b = 7.1325(4) Å, c = 19.527(3) Å, β = 103.628(2)°, V = 1774.8(5) Å3, Z = 4, R gt(F) = 0.0310, wR ref(F 2) = 0.0682, T = 296(2) K.

The oil sludge is considered as a hazardous waste, the improper disposal or insufficient treatment can pose a major problem to the oil production, transportation and processing processes, and may result in serious environmental concerns and human health risks. In the present study, washing treatment with a cleaning solution containing surfactant and alkali was investigated to remove the residual oil from the oil sludge obtained from Tahe Oilfield. The effects of the dosage of surfactant, cleaning temperature, stirring rate, stirring time and liquid-solid ratio on the performance in residual oil removing were analyzed. Sodium nonylphenol polyoxyethylene ether sulfate (AEOS) and alkali were used as the cleaning agents. The results show that the content of the residual oil in the sludge could be lowered from 14.3 wt% to 0.9 wt% after being washed twice under the optimum operation conditions with a 0.6 wt% AEOS and 3 wt% KOH solution for 30 min at 80 °C, a stirring rate of 210 rpm and a liquid-solid ratio of 3:1. Thermogravimetric (TGA) and infrared analyses confirmed that the oil components in the oil sludge can be mostly removed.

Acidification technology is an effective measure to increase the production of oil and gas wells or stimulate water injection wells. In order to prevent residual acid from damaging and contaminating the hydrocarbon reservoir, the residual acid should be discharged to the ground for centralized treatment after acidizing process. The present experimental work focused on acidified waste liquid composition analysis of the main pollutants so as to study pH adjustment process and optimization of parameters like dose of hydrogen peroxide and polyacrylamide flocculant. The results show that neutralization-oxidation-flocculation disposal technology enables the treated acidified waste liquid to reach the standard of the combined station sewage treatment system. This study provides theoretical basis and guidance for the process of acidified waste liquid re-injection treatment, the design of sewage treatment and spot application.

Pyrolysis is potentially an effective treatment of oily sludge for oil recovery, and its kinetics and efficiency are expected to be affected by additives. In the present study, the pyrolysis parameters, including heating rate, final pyrolysis temperature, and pyrolysis time of oily sludge in the presence of agricultural biomass, apricot shell, were systematically explored. As a result, maximum oil recovery is achieved when optimizing the pyrolysis conditionas15 K/min, 723 K, and 3 h for heating rate, final pyrolysis temperature, and pyrolysis time, respectively. Thermogravimetric experiments of oily sludge samples in the presence of various biomasses conducted with non-isothermal temperature programmes suggest that the pyrolysis process contains three stages, and the main decomposition reaction occurs in the range of 400–740 K. Taking Flynn–Wall–Ozawa analysis of the derivative thermogravimetry and thermogravimetry results, the activation energy (Ea) values for the pyrolysis of oily sludge in the ...

One of effective ways to reduce pollution from cigarette butts is introduced by recycling the cigarette butts. Inhibitor from recycled cigarette butts shows good inhibition properties, but we do not know whether CuCl can help to improve the inhibition efficiency. So, in this study, the impact of CuCl on recycled cigarette butts as corrosion inhibitor for N80 steel at 90 °C in 15% HCl is studied by weight loss, electrochemical noise, polarization, impedance, and X-ray photoelectron spectroscopy. All the results show that the inhibition efficiency of water extracts from cigarette butts in the presence of CuCl is higher than in absence of CuCl, and it can reach 95.3% when 9% water extracts with copper added is used. The X-ray photoelectron spectroscopy results indicate that the N80 steel specimen surface is undamaged and covered with a protective coat formed by copper-added water extracts from cigarette butts. CuCl has synergizing action on recycled cigarette butts as a corrosion inhibitor for N80 steel at 9...

The chemical compositions of cigarette butts water extracts mainly are aromatic amines including nicotine and its compounds. If oxygen exists, the aromatic amine compounds can be oxidized easily. Whether this oxidation would be beneficial in enhancing the corrosion inhibitive effect of the inhibitor is not known. In this study, the corrosion inhibitive effect of aerobic and anaerobic cigarette butts water extracts are compared on N80 steel at 90 °C in 15% (weight %) hydrochloric acid. The chemical compositions of the aerobic and anaerobic cigarette butts water extracts are also contrasted. Weight loss, X-ray diffraction, and electrochemical techniques (such as electrochemical noise, impedance, and potentiodynamic polarization) are used to evaluate the corrosion inhibitive effect of aerobic and anaerobic cigarette butts water extracts. Results show that the inhibition efficiency of the aerobic cigarette butts water extracts (92.9%) is higher than anaerobic cigarette butts water extracts (84.6%).