The Recycling of Acid Wastewater with High Concentrations of Organic Matter: Recovery of H2SO4 and Preparation of Activated Carbon

Little work has been focused on the recycling of hazardous acid waste with high concentrations of organic matter from petroleum refining. This study developed an innovative, effective, and simple method for the recycling of acid waste that can successfully resolve this significant problem in industry. After parameter optimization, the optimal process is as follows. (1) Through heat treatment at 170 °C, liquid acid waste was transformed into solid; (2) by washing the solids, 70% by weight of sulfuric acid was recycled; and (3) the solid residue after washing was activated by alkali (NaOH or KOH) at an alkali and organic carbon ratio of 2:1, at a temperature of 650 °C for 60 min, producing superior-grade activated carbon with a specific surface area of 1378 m2/g, a pore volume of 0.5107 cm2/g, an iodine number of 1800 mg/g, and a methylene blue adsorption capacity of 240 mg/g. Thus, in this way, both waste sulfuric acid and organic impurities are turned into valuable resources, and no hazardous waste gypsum residues are generated. This method both reduces carbon emissions and recycles valuable resources, which is of important environmental and economic significance.

Determination of organic impurities in cobalt production solutions using gas chromatography-mass spectrometry

Gas chromatography-mass spectrometry has been used for the analysis of cobalt production solutions by JSC “Kola MMC”. The presence of some new organic impurities in the circulating extractant was established and their influence on the physicochemical properties of the extractant has been determined. The paper considers reasons for the appearance of esters and chlorine derivatives impurities in solutions.

Substantial organic impurities at the surface of synthetic ammonium sulfate particles

Ammonium sulfate (AS) particles are widely used for studying the physical-chemistry processes of aerosols and for instrument calibrations. Small quantities of organic matter can greatly influence the studied properties, as observed by many laboratory studies. In this work, monodisperse particles (from 200 nm to 500 nm) were generated by nebulizing various AS solutions and organic impurities were quantified relative to sulfate using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS). The organic content found in AS solutions was also tentatively identified using a Liquid Chromatography–tandem Mass Spectrometry (LC-MS). The results from both analytical techniques were consistent and demonstrated that the organic impurities contained oxygen, nitrogen and/or sulfur, their molecular masses ranged from m/z 69 to 420, they likely originate from the commercial AS crystals. For AS particle sizes ranging from 200 nm to 500 nm, the total mass fraction of organic (relative to sulfate) ranged from 3.8 % to 1.5 % respectively. An inorganic-organic mixture model suggested that the organic impurities were coated on the AS particle surface with a density of 1.1 × 10−3 g m−2. A series of tests were performed to remove the organic content (using pure N2 in the flow, ultrapure water in the solutions, and very high AS quality), showing that at least 40 % of the organic impurities could be removed. In conclusion, it is recommended to use AS seeds with caution, especially when small particles are used, in terms of AS purity and water purity when aqueous solutions are used for atomization.

Mass Balance Method for Purity Assessment for Pesticide Analytical Standards

Imazamox, a widely used herbicide, is currently managed by the Pesticide MRLs and Positive List System of the Ministry of Food and Drug Safety, and the development of reliable standard materials for analysis is urgently required. To confirm the reliability of the mass balance method, we measured the purity of the imazamox reference material (RM) certified by an RM producer accredited with ISO Guide 34 and estimated measurement uncertainty. According to this method, the content of structurally similar organic impurities was measured using high-performance liquid chromatographic coupled with ultraviolet (HPLC-UV), and the moisture, volatile impurities, and non-volatile impurities were quantitatively analyzed using a thermogravimetric analyzer (TGA). Purity and measurement uncertainty were calculated based on analysis of the HPLC-UV and TGA results obtained, and the validity of these values was confirmed by comparing with the values provided in the RM certificate.

Investigation of organic impurity and its occurrence in industrial waste salt produced by physicochemical process

Industrial waste salt is classified as hazardous waste to the environment. The organic impurity and its occurrence in industrial waste salt affect the salt resource utilization. In this paper, composition quantitative analysis, XRD, TG-DSC, SEM/FIB-SEM coupled with EDS, FTIR, XPS and GC-Ms were chosen to investigate the organic impurity and its occurrence in industrial waste salt. The organic impurities owe small proportion (1.77%) in the specimen and exhibit weak thermal stability within the temperature of 600°C. A clear definition of organic impurity, including 11 kinds of organic compounds, including aldehyde, benzene and its derivatives etc., were detected in the industrial waste salt. These organic impurities, owing (C-O/C-O-C, C-OH/C = O, C–C/CHx/C = C etc.)-containing function group substance, are mainly distributed both on the surface and inside of the salt particles. Meanwhile, the organic substance may combine with metal cations (Ni2+, Mg2+, Cu2+ etc.) through functional groups, such as hydroxide, carbonyl etc., which increases its stability in the industrial waste salt. These findings provide comprehensive information for the resource utilization of industrial waste salt from chemical industry etc.

Research of Pyrophoric Compounds in Order to Reduce their Hazard

The constantly growing content of sulfur compounds and the increased water content in the extracted oil enhances the aggressiveness of the environments in which the technological equipment of oil depots and pipelines operates, resulting in a higher number of emergencies in the equipment of oil refineries. Thus, one of the most urgent problems is the corrosion damage to oil storage equipment and the associated consequences of flammable pyrophoric compounds formation. Finely dispersed flammable sulfides with organic impurities are formed in the equipment of the diesel fuel distillate hydrotreating unit thus accumulating on the bottoms and walls of tanks and reservoirs. This negatively affects the material balance of the hydrotreating process and increases fire and explosion hazards of the whole hydrotreating process at the refinery. For the first time, the elemental composition of pyrophoric deposits formed while storing petroleum products in the LCh-24-2000 unit was experimentally investigated. These sulfides are a flammable component of the equipment in the hydrotreating process, where diesel fuel distillates rotate. The obtained results of the test study as for the prevention of pyrophores spontaneous combustion indicate that hydrogen peroxide solutions have the highest efficiency. The practical significance of the results is in the use of experimental studies on the spontaneous combustion of pyrophoric samples in the development of the equipment cleaning terms during the hydrotreating process from pyrophoric deposits at the refinery. The experimental results of testing the ability of chemicals to prevent pyrophores spontaneous combustion can be used to reduce the risk of spontaneous combustion of pyrophoric compounds.