Phenol-formaldehyde Resin Production Research Articles

Gas-phase crosslinking of the lignin on the nanoscale fumed silica surface

A method for the polymerization modification of nanoscale fumed silica by crosslinking a lignin layer adsorbed on a nanosilica surface under a gas dispersion medium is described. A mixture of phenol and formaldehyde in the presence of HCl proved to be the most effective crosslinking agent. It has been suggested that the crosslinking of lignin molecules occurs by a mechanism similar to the production of phenol-formaldehyde resins.

Recycling Phenolic Wastewater from Phenol-Formaldehyde Resin Production

The sorption Phenolic wastewater is a kind of hazardous waste due to the presence of free phenol which is a highly toxic organic compound. Described in the literature and implemented, technology solutions for dephenolization are commonly based on thermal destruction. However, thermal treatment technologies have a range of disadvantages and the main ones of them are the losing of phenol and formaldehyde, which are valuable chemical raw materials and changing the balance of atmospheric oxygen and carbon dioxide. At the same time, owing to bonding properties, phenol and formaldehyde are used as polymer binders for manufacturing composite materials gradually replacing commercial synthetic resins. The paper presents results of the investigation related to developing a resource-saving technology for the recovery of phenol and formaldehyde from industrial phenolic wastewater by obtaining composite construction material and sodium phenolate. Sawdust and wastes from textolite manufacturing and processing were used as fillers and modifiers in a composite mixture. The presented technological process has been developed on the base of recycling using combined technologies through inter-industrial collaboration. This approach makes it possible to obtain high-quality recycled products from technogenic raw materials (degree of phenol conversion was 0.995) and to carry out complete dephenolization of the wastewater (residual phenol concentration was 2⋅10−2 mg/l), which can be used in the wastewater reuse system for the main chemical manufacturing.

Ресурсосберегающая технология обезвреживания фенолсодержащих промышленных сточных вод

We have developed a resource-saving, low-waste technology for the disposal of highly toxic phenol-containing wastewater that enables to utilize phenol and formaldehyde as an organic binder. The technology involves the use of technogenic raw materials («overresin» water from the production of phenol-formaldehyde resins, soft wood waste, waste from the production and processing of laminated plastics) and processes of regeneration, recovery and conversion of phenol. The optimal technological parameters of phenol sorption on wood sorbent and secondary poly/condensation were experimentally established. This in turn provides a high degree of neutralization and extraction of resin-forming components from wastewater and subsequent production wood-polymer thermoplastic structural composite and sodium phenolate on their basis.

Production of phenolic compounds using waste coir pith: Estimation of kinetic and thermodynamic parameters

The present study illustrates the production of phenolic compounds via slow pyrolysis of coir pith biomass in a bench-scale reactor. The primary objective of the study is to optimize the pyrolysis conditions to maximize the yield of bio-oil and phenolic compounds. Up to 88.14% phenolic compounds were obtained in the organic fraction of the bio-oil obtained at 350 °C. The phenolic compounds thus extracted can be used for the production of phenol-formaldehyde resins, which reduces the dependence on petroleum-based phenols for the manufacturing of resin. An independent kinetic analysis of the apparent pyrolysis reaction was also performed using thermogravimetry and isoconversional methodology. The calculated values of activation energy showed a variation from 28.41 to 200.09 kJ/mol, with the mean value being 140 kJ/mol. The thermodynamic parameters (ΔS, ΔH, and ΔG) were subsequently evaluated at different conversions using the activation energy values obtained from the kinetic analysis.

Determination of soil toxicty bioassay method under the influence of phenol

Soil is the basis of agriculture and the main source of food, providing95-97% of food resources for the world’s population. Significant negativeimpacts on soil pollution has toxic chemical compounds, many of whichare preserved for a long time in the soil.Phenol is a second class of danger to be carcinogenic and mutagenic.We studied the effect of harmful substances on the growth of radish seedssprouting. Experiments made in the laboratory on artificially contaminatedof phenol soil samples. It was established pattern of influence of the concentration of phenol in the soil extract on the growth of plants.The main sources of phenols into the environment are motor vehicleemissions, the production of phenol-formaldehyde resins, adhesives, plastics and steel, coke plants, etc. Phenol is in air, soil and water for a longtime if a large amount thereof ejected at a time, or if a large number ofemission occurred in a long time. When a one-time release of phenol inthe air less than a day, its concentration is halved on average. When injected into the soil phenol output 2-5 daysOne reason for the lack of data on contamination of soil phenol isquite complicated and expensive sample preparation required for its quantification. This places significant limitations on the number of samples analyzed and reduces the effectiveness of monitoring. At the moment, thereare only a few data on the results of determination of phenols in soils.The paper studied the effect of phenol on the growth of radish seedssprouting. The experiments were performed in the laboratory on artificially contaminated with phenol soil samples. Calculation of the degreeof change in seed germination and seedling root length as compared tocontrol samples allowed to correlate the contaminated with some degreeof toxicity. It was established pattern of influence of the concentration ofphenol in the soil extracts on the growth of plants.Кey words: phenol, toxicity, soil, radish, express test.

Chemical and thermal properties of lignins from oil palm biomass as a substitute for phenol in a phenol formaldehyde resin production

Lignins were extracted from oil palm empty fruit bunch after kraft and soda pulping process. The aim of this study was to characterise the chemical and thermal properties of these lignins as well as determine their suitability for partial incorporation into phenol formaldehyde resin. The analytical methods used were CHN analyser, FTIR spectroscopy, UV spectroscopy, TGA, DSC, GPC, 1H NMR and FESEM. The elemental analysis results showed that both lignins had similar contents of C, H and O. FTIR spectra also revealed that both lignins have similar functional groups. Nevertheless, both lignins showed different compositions in terms of molecular weight distribution (Mn, Mw and polydispersity), reactive site through Mannich reactivity analysis, surface morphology and Tg value. The phenolic hydroxyl group content in kraft and soda lignins is 4.1076mmol/g and 2.5830mmol/g, respectively. The TGA thermogram showed both lignins had high thermal stability. Based on these analyses, kraft lignin from oil palm empty fruit bunch showed tremendous potential as a partial substitute for phenol in phenol formaldehyde resin production.

Environmental performance assessment of hardboard manufacture

The forest-based and related industries comprise one of the most important industry sectors in the European Union, representing some 10% of the EU's manufacturing industries. Their activities are based on renewable raw material resources and efficient recycling. The forest-based industries can be broken down into the following sectors: forestry, woodworking, pulp and paper manufacturing, paper and board converting and printing and furniture. The woodworking sector includes many sub-sectors; one of the most important is that of wood panels accounting for 9% of total industry production. Wood panels are used as intermediate products in a wide variety of applications in the furniture and building industries. There are different kinds of panels: particleboard, fibreboard, veneer, plywood and blockboard. The main goal of this study was to assess the environmental impacts during the life cycle of wet-process fibreboard (hardboard) manufacturing to identify the processes with the largest environmental impacts. The study covers the life cycle of hardboard production from a cradle-to-gate perspective. A hardboard plant was analysed in detail, dividing the process chain into three subsystems: wood preparation, board forming and board finishing. Ancillary activities such as chemicals, wood chips, thermal energy and electricity production and transport were included within the system boundaries. Inventory data came from interviews and surveys (on-site measurements). When necessary, the data were complemented with bibliographic resources. The life cycle assessment procedure followed the ISO14040 series. The life cycle inventory (LCI) and impact assessment database for this study were constructed using SimaPro Version 7.0 software. Abiotic depletion (AD), global warming (GW), ozone layer depletion (OLD), human toxicity (HT), ecotoxicity, photochemical oxidant formation (PO), acidification (AC) and eutrophication (EP) were the impact categories analysed in this study. The wood preparation subsystem contributed more than 50% to all impact categories, followed by board forming and board finishing, which is mainly due to chemicals consumption in the wood preparation subsystem. In addition, thermal energy requirements (for all subsystems) were fulfilled by on-site wood waste burning and, accordingly, biomass energy converters were considered. Several processes were identified as hot spots in this study: phenol-formaldehyde resin production (with large contribution to HT, fresh water aquatic ecotoxicity and PO), electricity production (main contributor to marine aquatic ecotoxicity), wood chips production (AD and OLD) and finally, biomass burning for heat production (identified as the largest contributor to AC and EP due to NO X emissions). In addition, uncontrolled formaldehyde emissions from manufacturing processes at the plant such as fibre drying should be controlled due to relevant contributions to terrestrial ecotoxicity and PO. A sensitivity analysis of electricity profile generation (strong geographic dependence) was carried out and several European profiles were analysed. Novel binding agents for the wood panel industry as a substitute for the currently used formaldehyde-based binders have been extensively investigated. Reductions of toxic emissions during drying, mat forming and binder production are desirable. The improved method would considerably reduce the contributions to all impact categories. The results obtained in this work allow forecasting the importance of the wood preparation subsystem for the environmental burdens associated with hardboard manufacture. Special attention was paid to the inventory analysis stage for each subsystem. It is possible to improve the environmental performance of the hardboard manufacturing process if some alternatives are implemented regarding the use of chemicals, electricity profile and emission sources in the production processes located inside the plant. This study provides useful information for forest-based industries related to panel manufacture with the aim of increasing their sustainability. Our research continues to assess the use phase and final disposal of panels to complete the life cycle assessment. Future work will focus on analysing the environmental aspects associated with plywood, another type of commonly used wood panel.

The application of pyrolysis-molecular beam mass spectrometry for characterization of bark phenolysis products

Barks from four common Mediterranean trees subjected to phenolysis under acidic conditions at moderate temperature (130°C or 150°C) were evaluated with pyrolysis-molecular beam mass spectrometer (py-MBMS). The results indicated that both concentration of acid catalyst and the phenolysis temperature have an impact on the chemical composition of both the isolated oils and the solid residue, with the acid concentration having the greatest influence. The primary phenolysis reaction products included phenolics and furans. As expected, at higher acid concentrations the phenolysis products contained less carbohydrate and included more phenolic fragments. These phenolysis oils should be useful as feedstocks for the production of phenol formaldehyde resins. The py-MBMS method was found to be an effective and convenient method to understand bark phenolysis.

Improvement of river water quality - the results of industrial effluent minimisation

The harmful effects of wastewaters on receiving streams, caused by insufficient quality of effluents, inadequate dimensioning and overloading of present treatment plants, as well as the trends of science and technology call for improvement of the treatment technologies, development of advanced treatment processes and above all for waste minimisation in industrial processes to meet the increasing water quality standards. Microbial degradation is crucial in the prediction of the duration and, thereby, the effects of organic pollution in natural waters. Evaluating the fate of biodegradable organic pollution downstream from the discharge seems an appropriate way to follow the effect of pollution and its hazard assessment that dictates needed sanitation measures. This paper is concerned with effluent discharges and with the water receiving such discharges. A practical method for the study of the fate of biodegradable industrial pollution in receiving stream is demonstrated. The impact of wastewater from the synthetic phenol-formaldehyde resin production on Borovnišica river is presented. By comparative investigations, before and after introduction of sanitation measures, the beneficial impact of industrial effluent minimisation and treatment is shown evidently.

Redox Cycling of Phenol Induces Oxidative Stress in Human Epidermal Keratinocytes

A variety of phenolic compounds are utilized for industrial production of phenol-formaldehyde resins, paints, lacquers, cosmetics, and pharmaceuticals. Skin exposure to industrial phenolics is known to cause skin rash, dermal inflammation, contact dermatitis, leucoderma, and cancer promotion. The biochemical mechanisms of cytotoxicity of phenolic compounds are not well understood. We hypothesized that enzymatic one-electron oxidation of phenolic compounds resulting in the generation of phenoxyl radicals may be an important contributor to the cytotoxic effects. Phenoxyl radicals are readily reduced by thiols, ascorbate, and other intracellular reductants (e.g., NADH, NADPH) regenerating the parent phenolic compound. Hence, phenolic compounds may undergo enzymatically driven redox-cycling thus causing oxidative stress. To test the hypothesis, we analyzed endogenous thiols, lipid peroxidation, and total antioxidant reserves in normal human keratinocytes exposed to phenol. Using a newly developed cis-parinaric acid-based procedure to assay site-specific oxidative stress in membrane phospholipids, we found that phenol at subtoxic concentrations (50 microM) caused oxidation of phosphatidylcholine and phosphatidylethanolamine (but not of phosphatidylserine) in keratinocytes. Phenol did not induce peroxidation of phospholipids in liposomes prepared from keratinocyte lipids labeled by cis-parinaric acid. Measurements with ThioGlo-1 showed that phenol depleted glutathione but did not produce thiyl radicals as evidenced by our high-performance liquid chromatography measurements of GS.-5, 5-dimethyl1pyrroline N-oxide nitrone. Additionally, phenol caused a significant decrease of protein SH groups. Luminol-enhanced chemiluminescence assay demonstrated a significant decrease in total antioxidant reserves of keratinocytes exposed to phenol. Incubation of ascorbate-preloaded keratinocytes with phenol produced an electron paramagnetic resonance-detectable signal of ascorbate radicals, suggesting that redox-cycling of one-electron oxidation products of phenol, its phenoxyl radicals, is involved in the oxidative effects. As no cytotoxicity was observed in keratinocytes exposed to 50 microM or 500 microM phenol, we conclude that phenol at subtoxic concentrations causes significant oxidative stress.

Thermocatalytic treatment of hazardous industrial wastewaters

Industrial wastewaters containing high concentrations of chemical substances were treated using a method of thermocatalytic oxidation. A number of selected examples of the application of this method have been presented. Wastewaters containing non-ionic detergents were oxidized in the presence of catalyst. High degrees of oxidation over 97% were obtained. The consumption of electrical energy, was 10 kWh kg COD under optimum conditions. Exhausted cooling oil-emulsions, were treated autothermically in the presence of catalyst. A high degree of oxidation of organic substances over 99% was obtained. Copper was recovered from the wastewaters electrochemically with an efficiency of 90%. The wastewaters from the production of phenol-formaldehyde resins, were treated in the presence of catalysts. High degrees of oxidation over 99% were obtained. In each of examples presented copper-zinc catalyst was used at a temperature of 400–700 °C. The examples testify to very high efficiency of the method for thermocatalytic oxidation of industrial wastewaters hazardous for the aqueous environment.