The paper presents a numerical approach to the analysis of the statistical effect of functional groups on the sorption of methanol and water on hard coal samples. The material used for the analysis was obtained from numerous samples of hard subbituminous and bituminous coals up to anthracite from different Polish coal mines and includes sorption isotherms of water and methanol vapors, as well as carbon dioxide and methane on these samples. Measurements were made of the sorption isotherms of water and methanol vapors and the data set has been supplemented with the sorption isotherms of water, methane and carbon dioxide taken from the literature for the precise estimation of the model parameters. More precise estimation is reached by using a strong setting of the coal structure parameters for a bigger number of sorption system, and in each case the same parameters of coal geometry are constant with an exact fitting of sorption isotherm. The adsorption-absorption model of the sorption in coal (Multiple Sorption Model-MSM) is used in the numerical experiments and the parameters of hard coal structure and the sorption systems are estimated. It has been stated that water as a polar substance together with methanol, as well as carbon dioxide and methane give good estimates of coal structure and let us quantify the polar effect of surface groups present in hard coal. The polar effect is introduced in the model in the range of adsorption and expansion sub-processes. The presence of oxygen groups in the bulk of coal matter has no significant effect and can be neglected. A weak decreasing tendency of polar factors ratio for water and methanol is discovered.

Lactic acid is a naturally existing organic acid, which may be used in many different branches of industrial application. It can be made in the sugar fermentation process from renewable raw lactic acid, which is an indispensable raw material, including in the agricultural, food, and pharmaceutical industries. It is an ecological product that has enjoyed great popularity in recent years. In 2010, the US Department of Energy published a report about lactic acid to be a potential building element for future technology, whose demand grows year by year. The lactic acid molecule naturally exists in plants, microorganisms, and animals and can also be produced by carbohydrate fermentation or chemical synthesis from coal, petroleum products, and natural gas. In industry, lactic acid can be produced by chemical synthesis or fermentation. Although racemic lactic acid is always produced chemically from petrochemical sources, the optically pure L(+) – or D(−) – lactic acid forms can be obtained by microbial fermentation of renewable resources when an appropriate microorganism is selected. Depending on the application, one form of optically pure LA is preferred over the other. Additionally, microbial fermentation offers benefits including cheap renewable substrates, low production temperatures, and low energy consumption. Due to these advantages, the most commonly used biotechnological production process with the use of biocatalysts, i.e., lactic acid bacteria. The cost of raw materials is one of the major factors in the economic production of lactic acid. As substrate costs cannot be reduced by scaling up the process, extensive research is currently underway to find new substrates for the production of LA. These searches include starch raw materials, lignocellulosic biomass, as well as waste from the food and refining industries. Here, the greatest attention is still drawn to molasses and whey as the largest sources of lactose, vitamins, and carbohydrates, as well as glycerol – a by-product of the biodiesel component production process. Focusing on the importance of lactic acid and its subsequent use as a product, but also a valuable raw material for polymerization (exactly to PLA), this review summarizes information about the properties and applications of lactic acid, as well as about its production and purification processes. An industrial installation for the production of lactic acid is only planned to be launched in Poland. As of today, there is no commercial-scale production of this bio-raw material. Thus, there is great potential for the application of the lactic acid production technology and research should be carried out on its development.

The content of polyphenols, lactic acid, and antioxidant properties in fermented juice increases more at 30 °C than at 35 °C during the lactic fermentation process in butanol extract and broccoli juice. The concentration of polyphenols is expressed by phenolic acid equivalents as gallic acid-Total Phenolic Content (TPC), ferulic acid (CFA), p-cumaric acid (CPA), sinapic acid (CSA), and caffeic acid (CCA). The polyphenols present in fermented juice exhibit antioxidant properties and the ability to reduce free radicals using total antioxidant capacity (TAC) assay, while also the percentage of the DPPH (2,2-Diphenyl-1-picrylhydrazyl) radical and ABTS (2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) cation radical scavenging activity. Lactic acid concentration (LAC), total flavonoid content as quercetin equivalents (QC), and acidity increases during the work of Lactiplantibacillus plantarum (previously Lactobacillus plantarum) in broccoli juice. The pH was monitored during the process of fermentation in both temperatures (30 °C and 35 °C). Densitometric measurements of lactic bacteria (LAB) showed increasing concentration at 30 °C and 35 °C after 100 h (~4 h), but the value concentration dropped after 196 h. The Gram staining showed only Gram-positive bacilli Lactobacillus plantarum ATCC 8014. The Fourier transform infrared (FTIR) spectrum for the fermented juice showed the characteristic carbon–nitrogen vibrations that may originate from glucosinolates or isothiocyanates. Among the fermentation gases, more CO₂ was released from fermenters at 35 °C than at 30 °C. The biopreservation used Lactiplantibacillus plantarum to prevent the problem of food waste of plant origin. The probiotic bacteria used in fermentation have a very beneficial effect on health and the human body.

The purpose of the work presented in this paper was to adapt the Multiple Sorption Model (MSM), originally developed for hard coals, to study sorption in lignites. It also includes an analysis of the sorption process of small molecule compounds in lignites. Measurements were made of the sorption isotherms of carbon dioxide in two samples of lignite from Polish collieries at different temperatures (298, 313 and 323 K) and in the pressure range up to 5 MPa. Subsequently, simulations of the isotherms for selected carbon dioxide-lignite systems were performed using the MSM. They were evaluated using the empirical isotherms until agreement of the isotherms was attained and the parameters of the sorption system reached reasonable values. Surprisingly, a low contribution of absorption was found in the overall sorption process probably as an effect of the high porosity of the sample and the presence of a large number of high-energy sites on the coal surface. Sorbate molecules occupied these high-energy sites on the surface and did not migrate to the absorption subsystem.

Carbonaceous adsorbents have been pointed out as promising adsorbents for the recovery of methane from its mixture with carbon dioxide, including biogas. This is because of the fact that CO₂ is more strongly adsorbed and also diffuses faster compared to methane in these materials. Therefore, the present study aimed to test alternative carbonaceous materials for the gas separation process with the purpose of enriching biogas in biomethane and to compare them with the commercial one. Among them was coconut shell activated carbon (AC) as the adsorbent derived from bio-waste, rubber tire pyrolysis char (RPC) as a by-product of waste utilization technology, and carbon molecular sieve (CMS) as the commercial material. The breakthrough experiments were conducted using two mixtures, a methane-rich mixture (consisting of 75% CH₄ and 25% CO₂) and a carbon dioxide-rich mixture (containing 25% CH₄ and 75% CO₂). This investigation showed that the AC sample would be a better candidate material for the CH₄/CO₂ separation using a fixed-bed adsorption column than the commercial CMS sample. It is worth mentioning that due to its poorly developed micropore structure, the RPC sample exhibited limited adsorption capacity for both compounds, particularly for CO₂. However, it was observed that for the methane-rich mixture, it was possible to obtain an instantaneous concentration of around 93% CH₄. This indicates that there is still much potential for the use of the RPC, but this raw material needs further treatment. The Yoon–Nelson model was used to predict breakthrough curves for the experimental data. The results show that the data for the AC were best fitted with this model.

The subject of the article is the thermodynamic analysis of the sorption of aliphatic hydrocarbons in hard coals from polish mines. The analysis is based on a Multisorption model designed for describing small molecule sorption in different types of carbonaceous materials (e.g. hard coals, lignites or active carbons). Experimental isotherms of hydrocarbons: hexane, heptane, octane and benzene, in hard coals of different rank, together with water and methanol vapor isotherms measured at room temperature (25 °C), are taken as comparative data for simulations. Results of the analyses reveal the complicated behavior of linear molecules in the sorption system. The location of molecules on the sorbent surface brings a spectrum of problems associated with the incomplete filling of pores, the coiling up of chains, the formulation of plates or globules, and the blocking of micropores. All these effects have an influence on the level and character of sorption, often in opposing ways. The sorption of small inorganic molecules is taken into account in the objective of achieving a more precise identification of the structure of coal. Semi-simultaneous computations for all types of sorbates have already been carried out.