Olive Oil Solid Waste Research Articles

Influence of Chemical Treatment on the Spectral and Thermal Behavior of Activated Carbon Obtained from Olive Oil Solid Waste

Solid waste remained after the extraction of oil from olive oil fruits (OOSW), was used to obtain active carbon depending on chemical activation using H3PO4, KOH and ZnCl2 as activating agents. The changes in composition due to chemical treatment and pyrolysis were investigated by chemical analysis, spectral (IR), and thermal analysis (DTA). Thermodynamic parameters of formation (activation energy (ΔEa*), enthalpy change (ΔH*), entropy change (ΔS*) and free energy change (ΔG*) related to the thermal decomposition process were calculated. Adsorption of both iodine and methylene blue at very low concentrations were done, the quantity of the iodine adsorbed (iodine number) indicated the micropores content of carbon by the uptake of iodine from the solution. It is equivalent to surface area of carbon between 900m2/g and 1100 m2/g. To characterize activated carbons as well as determining the adsorption capacity adsorption of methylene blue was done.

The short-term effects of pyro-and hydrochars derived from different organic wastes on some soil properties

A short-term incubation study was carried out to investigate the effects of different biochar (pyrochar and hydrochar) amendments on soil properties. Pyrochars and hydrochars derived from sewage sludge (PSS and HSS), poultry manure (PPM and HPM), and olive oil solid waste (POW and HOW) through slow pyrolysis and hydrothermal carbonization (HTC) were mixed with soil in three different doses (1, 2, and 4%) and subjected to a 120 day incubation period. Selected soil physical (water-stable aggregate [WSA]) and chemical (pH, EC [Electrical conductivity], CaCO3, total N, soil organic matter [SOM], C:N ratio, and available P) were investigated at the end of incubation, while soil biological properties (urease [UR], alkaline phosphatase [ALP] and β-glucosidase [βG] enzyme activities) were evaluated in a time-course sampling, at 1, 60, and 120 days of the incubation. The results generally indicated that total N and soil available P contents were more responsive to pyrochars and hydrochars produced from different biomass wastes. All pyrochars showed significantly higher total N and available P over hydrochars depending on the application doses and only HOW showed a prominent enhancement in SOM over POW. In general, soil ALP activity did not show distinct changes in pyrochar amended conditions, whereas it seemed to increase significantly by the amendments of hydrochars, especially HSS (p < 0.05), over the control and application dose. The βG activity displayed a similar pattern with that of ALP activity in that increasing additions of hydrochars produced from all three waste biomasses significantly stimulated (p < 0.05) βG activity over those of their corresponding pyrochars. Unlike from ALP and βG activities, UR tended to decrease significantly (p < 0.05) in all pyrochar added treatments but depending on the waste biomass type and application dose; it showed different change patterns under hydrochar treatments. Overall, the results showed that the hydrochar obtained from HTC is more effective on the biological properties of soil compared to the biochar obtained by pyrolysis. On the other hand, it is possible to conclude that pyrochar was a very stable and recalcitrant C source than hydrochar according to microbial activities and could be an efficient, long-term strategy to sequester C in soils.

Removal of phenolic compounds from aqueous solution using MgCl2-impregnated activated carbons derived from olive husk: the effect of chemical structures.

Activated carbon (BC) prepared from olive oil solid waste (olive husk) by slow pyrolysis was chemically activated using MgCl2 (BC-MgCl2). The BC and BC-MgCl2 were used as adsorbents for removal of three phenolic compounds, namely, phenol (P), p-methoxyphenol (PMP) and p-nitrophenol (PNP), from aqueous solution. The uptake of these three phenolic compounds by the BC and BC-MgCl2 was better expressed by the Langmuir and Dubinin-Radushkevich (D-R) isotherm models than by the Freundlich isotherm, and the kinetics of the adsorption process followed the pseudo-second order kinetic model. The maximum monolayer adsorption capacity of P, PMP and PNP were increased from 24.938, 45.455 and 61.728 on BC to 43.860, 98.039 and 121.951 mg/g on BC-MgCl2 by factors of 1.76, 2.16 and 1.98, respectively. Therefore, the chemical activation of BC by MgCl2 is indeed of importance for improving its adsorption performances. For both adsorbents, the adsorption phenomenon for different substituted phenols is a strong function of solubility, polarity, molecule structure, and size. At the tested temperatures (25, 35 and 45 °C), the negative values of ΔG° and positive values of ΔH° and ΔS° for the adsorption of P, PMP and PNP on BC and BC-MgCl2 demonstrated that the adsorption was a spontaneous, endothermic and entropy-increasing process.

Potentiality of “orujillo” (olive oil solid waste) to produce hydrogen by means of pyrolysis

The extraction of olive oil generates great amounts of solid waste and wastewater. The objective of this work is to evaluate the potentiality of slow pyrolysis of the solid oil waste, known as “orujillo”, to produce hydrogen rich gases. The effect of temperature and of different treatments of pyrolysis vapors on the yield and composition of the gases has been experimentally studied. “Orujillo” was pyrolyzed at 500 °C and 700 °C, and the pyrolysis vapors produced were directly fed to a second reactor where they were treated at 800 °C in different ways: just thermally, thermally treated through a refractory alumina bed and thermo-catalytically treated through a three layer bed (alumina + SiC mixed with Ni catalyst + alumina). The catalyst used was a commercial prereduced nickel-catalyst which contains 44 wt% Ni over calcium aluminate support (CaO/Al2O3). Concerning the effect of temperature, it has been proved that the raise in temperature leads to a decrease in the liquid yields and an increase in the gas yields, as well as to an increase in H2 and a decrease in CO2 content of the gases. With respect to the vapors treatments it has been observed that as a general rule any of the treatments reduces liquid and increases gas yields, and concerning gas composition, H2 content increases, CO slightly increases and CO2 decreases. These effects are more pronounced when the Ni-catalyst is used. With the Ni-catalyst about 50 wt% gas yield is obtained, with ≈ 50 vol% H2 both at 500 and at 700 °C.

Monitoring composting process of olive oil solid waste using FT-NIR spectroscopy

ABSTRACTFT-NIR (Fourier Transform-Near Infrared) spectroscopy has been used for the prediction of properties of various materials. Olive oil solid waste compost (OSWC) can be a good and available source for soil organic matter in Mediterranean countries. This study was aimed at developing a fast and nondestructive method for determining compost carbon to nitrogen (C/N) ratio, total nitrogen (TN), inorganic nitrogen, total carbon (C), pH and electrical conductivity (EC) using FT-NIR spectroscopy. Composts were sampled weekly and some chemical analyses were performed on the samples using standard methods. Also, reflectance spectra of the same compost were acquired using FT-NIR spectroscopy right after the standard measurements. Organic matter functional groups of OSW and OSWC were compared using 13C-NMR spectroscopy. Calibration models between the standard measurements and the spectral measurements performed on samples were established applying Partial Least Squares (PLS) method. According to prediction models following determination coefficients (R2) of 0.86, 0.82, 0.81, 0.77, 0.75, 0.65 and 0.51 were obtained respectively for nitrate (NO−3), pH, ammonium (NH+4), total N, C/N ratio, total C and EC. With this study, it was shown that FT-NIR spectroscopy has the potential of sensing OSWC parameters nondestructively.

The use of industrial thermal techniques to improve the bioactive compounds extraction and the olive oil solid waste utilization

Abstract The development of thermal treatments is helping to optimize the management of waste generated by the two-phase olive oil extraction system. A new treatment reactor, based on the steam explosion system, has been scaled up to the industrial level and offers several physical and chemical advantages. The reactor has been adapted to work into the pomace oil extractors. Chemical advantages include the efficient solubilization of simple phenols, like hydroxytyrosol, and sugars in the liquid fraction, and a significant reduction of humidity and toxicity of the residual solid fraction, in which cellulose and oil are concentrated, making the solid residual waste more suitable for subsequent bioprocess applications. All of these parameters will lead to the widespread use of steam treatment in the near future to improve the management and obtain the maximum exploitation of this byproduct.

Removal of metals and metalloids from acidic mining lake (AML) using olive oil solid waste (OSW)

The acidic mining lakes have low pH values and high metal and metalloid concentrations. In this study, the ability of low-cost olive oil solid waste (OSW) to remove Al, As, Cd, Fe, B and Ti ions from aqueous solutions in short term has been evaluated. Adsorption capacities (mg g−1) of OSW (1:5–1:10 w/v) were 764.06–411.75 for Al, 0.26 for As, 0.07–0.14 for Cd, 2181.5–2406.5 for Fe, 23.70–82.50 for B and 0.12–0.0.34 for Ti. OSW addition increased acidic mine water (AMW) pH from 2.41 to 3.2 with 1:5 and from 2.41 to 2.7 to 1:10 mixing ratio, respectively, after 10 min. The best gradual decrease has been observed with different ratio of OSW applications on B and Ti concentrations. OSW adsorbs 32.41% and 62.68% of B at the ratio of 1:5 and 1:10 and 55.29% and 83.04% of Ti at the ratio of 1:5 and 1:10 (OSW:AMW) mixtures, respectively. The results show that OSW has great potential for metal removal from acidic mine water.

The effect of olive oil solid waste application on soil properties and growth of sunflower (Helianthus annuus L.) and bean (Phaseolus vulgaris L.)

Research on the reuse and recycling of agricultural by-products and industrial wastes are becoming increasingly important due to storage and environmental problems associated with these wastes. This study investigated the effect of olive oil solid waste (OSW) application rates on the macro- and micro-elemental contents and plant growth of bean (Phaseolus vulgaris L.) and sunflower (Helianthus annuus L.) and soil properties. OSW was mixed with soil at rates of 0, 3, 5 and 7% w/w. Sunflower was grown for 45 days and bean for 30 days in pots. Relative phosphorus (P), calcium (Ca), zinc (Zn) and boron (B) contents by mass of sunflower plants increased while nitrogen (N) and carbon (C) content decreased. In contrast in bean, P, B and Zn contents were increased but C, N, Ca, and manganese (Mn) contents decreased. Total carbon (TC), total nitrogen (TN) and electrical conductivity (EC) increased while pH decreased pot soils after harvesting. Direct application of OSW to clay loam soil has significant negative impacts on growth of sunflower and bean. However, soil properties were enhanced and organic matter content increased.

A study of the precursors of the natural antioxidant phenol 3,4-dihydroxyphenylglycol in olive oil waste

3,4-Dihydroxyphenylglycol (DHPG) is a potent antioxidant recently found in the free form in olive oil and table olives. DHPG can be recovered from olive oil solid waste by a hydrothermal treatment. It was observed that an increase in the concentration of DHPG occurred when alperujo aqueous extracts were subjected to mild thermal conditions (post-treatment). This fact indicates that certain solubilized compounds or precursors containing DHPG which is released with the post-treatment. In the present study, the precursors of DHPG were identified and characterized after extraction from alperujo using thermal treatment and purification by fractionation on Amberlite® XAD16 polyamide and semi-preparative reverse-phase HPLC columns. Their structures were elucidated using HPLC coupled to diode array detector (DAD) and electrospray ionization mass spectrometry (ESI-MS). The results identified three compounds as precursors, and their structures can be attributed to the diastereoisomeric forms of the two β-hydroxy derivatives of verbascoside and isoverbascoside (β-hydroxyacteoside and β-hydroxyisoacteoside), and 2″-hydroxyoleuropein, all of which contain a DHPG moiety, potentially explaining the increases in the concentration of this phenolic compound in olive oil waste.

Impact of solid and liquid olive oil waste applications on important soil properties

Some of the agricultural waste has important economic potentials to be used as a source of plant nutrients and as soil conditioner. Olive oil solid and liquid waste (OSLW) is one of them. Some of the characteristics of this material are favorable for agriculture, such as low pH and high content of organic matter, N, P, K, and Mg. This study was carried out at the Research Farm of Faculty of Agriculture, Adnan Menderes University Aydin for two years. Olive oil solid and liquid waste was applied as liquid and solid forms with three doses (liquid OSLW 0–2.5–5.0–7.5 l m−2, solid OSLW 0–1.5–3.0–4.5 kg m−2). Results indicate that organic matter contents were slightly risen up with the applications of olive oil waste while soil pH decreased with both liquid and solid forms of waste applications. There were also increases in organic matter, N, P, K, and Mg contents with rise of application doses. It was also determined that the undesired effects of Na and EC in soils, important for environmental pollution, disappeared through the experimental period.

Effects of olive oil solid waste on growth and nutrient uptake of faba bean, onion, and radish plants

Although, olive oil industry is crucial for Turkey, olive oil solid waste or olive vegetation water, a by-product of the industry, leads to environmental pollution during olive oil production. This study investigated the fields where olive oil solid waste was used as an organic substance. Olive oil solid waste in different concentrations (0, 10, 20, 30 and 40 t ha-1) were applied to faba bean, onion and radish plants grown (in 1 m2 plots) in the field conditions. Germination rates and growth of the plants were monitored. The application at the rates of 10 to 30 t ha-1were determined as the most appropriate rates for both faba bean and onion. The higher rates of application negatively affected germination and growth of plants. The application at 20 t ha-1 concentration of olive oil solid waste provided the best results for faba bean and onion plants. However, none of the application rates were found suitable for radish. Keywords: Olive oil solid waste; germination; plant growth; plant analysis

Valorization of olive oil solid waste using high pressure–high temperature reactor

The production of olive oil leads to considerable amounts of solid wastes rich in bioactive compounds with antioxidant properties, which have been partly used as inefficient polluting heating fuels for many years. This work was aimed to study the effect of extraction time and temperature on phenolics recovery from olive pomace. For this propose, different tests were performed, varying time from 15 to 120 min and temperature from 100 to 180 °C, using a high pressure–high temperature agitated reactor under a modified atmosphere. Total polyphenols, o-diphenols and total flavonoids were quantified. Maximum total polyphenols yield (45.2 mg CAE/g DP) was achieved at 180 °C and 90 min. HPLC analysis showed that oleuropein (2433 mg/100 g DP) and tyrosol (485 mg/100 g DP) were predominant phenolics in the extracts. Methanolic extracts, after additional purification processes, can be used in food, cosmetic and pharmaceutical industries. Solid residues, after phenolics extraction, are considered to have little environmental impact.

Weibull mixture model for isoconversional kinetic analysis of biomass oxidative pyrolysis

Abstract In this work, the possibility of applying the weighted sum of three cumulative Weibull distribution functions for the fitting of the kinetic conversion data of biomass oxidative pyrolysis has been investigated. The kinetic conversion data of the thermal decomposition of olive oil solid waste in oxygen atmosphere for different heating rates have been analysed. The results have shown that the experimental data can be perfectly reproduced by the general fitting function. Therefore, it is possible to obtain the corresponding conversion rates of biomass oxidative pyrolysis by differentiating directly the fitted kinetic conversion data. Additionally, the logistic mixture model has been applied to the same experimental data. It can be found that the newly proposed function can provide a better fit of the data than the logistic mixture model. Based on the fitting of Weibull mixture model, the kinetic triples, i.e. E, A and f(α), of oxidative pyrolysis of olive solid waste, were obtained by means of Fried...

Comparison between emissions from the pyrolysis and combustion of different wastes

A comparison between different emission rates of various pollutants obtained from various wastes is presented. The studied wastes were the following: polyethylene (PE), tyres, sewage sludges, polyvinyl chloride (PVC), cotton textiles, polyester textiles, meat and bone meals (MBMs), varnish wastes, olive oil solid waste (pomace), waste lube oils and paper waste. The decomposition of these wastes was studied in a horizontal laboratory scale reactor under fuel-rich conditions, and the analysis of the pollutants evolved comprised several compounds such as light hydrocarbons, polyaromatic hydrocarbons (PAHs) and polychlorinated dibenzo- p-dioxins and dibenzofurans (PCDD/Fs). From the studied wastes, a general behaviour was deduced regarding the evolution of semi-volatile compounds with the increase of temperature, both in pyrolysis and combustion. The results showed that the emissions of some compounds decreased with increasing oxygen ratio. Compounds with this behaviour were mainly volatile hydrocarbons, which were consumed in presence of oxygen. In addition, compounds with oxidized structure were present a maximum with oxygen ratio. Intermediate compounds with very high resistance to the oxygen under the working conditions increased continuously in concentration when the oxygen ratio increased. With reference to behaviour versus temperature there were compounds whose yields decreased with increasing temperature, such as volatile hydrocarbons and semi-volatile compounds. Also some pollutants are promoted at intermediate temperatures, e.g. light hydrocarbons, semi-volatile compounds, many monoaromatic compounds and many polyaromatic hydrocarbons.

Influence of olive oil solid waste applications on soil pH, electrical conductivity, soil nitrogen transformations, carbon content and aggregate stability

Some of the agricultural wastes have important economic potentials to be used as a plant nutrition and/or soil conditioner. Olive oil solid waste (OSW) is one of them. The aim of this study was to determine effects of OSW on soil pH, electrical conductivity (EC), improving soil nitrogen (N) status, soil aggregate stability and soil carbon contents. Different rates of OSW (control, 2%, 4% and 8%, w/w) were applied to coarse soils and incubated for 2 months. OSW applications decreased soil pH values. The mean EC value of soil measured 2 months after the incubation was greater than that of the first month. Application of OSW at the rate of 8% has significantly increased soil total organic nitrogen contents. OSW applications at the rate of 8% (w/w) significantly increased both mean SOC content (3.5%) and aggregate stability (88%) after 2 months of incubation ( p < 0.01). Therefore, OSW has great potential to improve soil structure of coarse textured soil in short term.

Emissions from pyrolysis and combustion of olive oil solid waste

The pyrolysis and combustion of solid residues from olive oil processing was studied. The objective of the study was to identify the possible hazardous compounds present in incomplete combustion of this material. The study comprises the identification and quantification of the combustion pollutants produced in a laboratory horizontal furnace. The thermal treatment was found to produce low amounts of pollutants, and in fact a small quantity of oxygen was enough to diminish the yields to extremely low levels, showing this way that the combustion efficiency was high. The ashes contained a significant quantity of potassium. No toxic or dangerous inorganic compounds were detected.

Kinetics of the pyrolysis and combustion of olive oil solid waste

The pyrolysis and combustion of solid residues from olive oil processing were studied by dynamic TG–DTG at heating rates between 5 and 20 °C min −1 at atmospheric pressure. Two different atmospheres were used: on the one hand, an inert atmosphere (He) in order to study the pyrolysis of the material, and on the other hand an oxidative atmosphere (He:O 2 in different ratios) to study its combustion. Pyrolysis follows a two parallel and independent fractions model, with kinetic parameters typical of holocelulose (12%) and lignin (48%). Combustion adds a third reaction to the model, which is cocurrent, due to the combustion does not start until the main devolatilization is finished, attaining kinetic parameters and reaction orders typical of a gasification reaction.