Peach Stones Research Articles

Cold oxygen plasma induces changes on the surface of carbon materials enhancing methanogenesis and N2O reduction in anaerobic sludge incubations

AbstractBACKGROUNDConductive materials, such as activated carbon (AC), graphene and biochar, have recently been applied for enhancing methane (CH4) production in anaerobic digesters. However, few efforts have been made to develop engineered conductive materials for these purposes. The aim of this work was to synthesize carbon materials from pecan nut shells and peach stones to apply them in anaerobic sludge incubations for enhancing the methanogenic activity, as well as the reduction of nitrous oxide (N2O).RESULTAddition of conductive materials increased up to six‐fold the maximum CH4 production rate. Moreover, oxidation of these carbon materials with cold oxygen plasma enriched their surface with redox functional groups (e.g. quinones), so that their application further increased the methanogenic production rate up to 11‐fold as compared to controls lacking conductive materials. Furthermore, the reduction rate of N2O was increased several orders of magnitude in the presence of synthesized carbon materials, which constitutes the first demonstration that conductive materials can significantly increase the reduction rate of this greenhouse gas.CONCLUSIONResults indicate that there is great potential to develop engineered conductive materials to enhance both the production of CH4 and the reduction of N2O from wastewater treatment plants (WWTP), which may contribute to achieve more efficient processes. © 2019 Society of Chemical Industry

Chromatographic characterization of pyroligneous liquid obtained from carbonization of peach stone

The peach stone is considered an agroindustrial residue originating from the industrial process of peach in halves in syrup. It does not have an adequate destination, its final disposal is incorrect and may cause contamination in the environmental compartments. In this way, the burning of this raw material as biomass enables its reuse, besides adding value to the residue. Among the processes used for the application of this residue is the carbonization process, which allows to obtain co-products with higher added value, such as pyroligneous liquid, which represents a fraction of organic compounds condensed from the smoke emitted during carbonization. The quality of the liquid depends on the process conditions and the biomass used. Therefore, the objective of this study was to characterize the sample of pyrolignous liquid obtained from the carbonization of the peach stone, on an industrial scale, qualitative and semi quantitative. Preliminary characterization (pH, conductivity, color, density and contents of tar, organic matter and acidity) and a chemical characterization by gas chromatography coupled to mass spectrometry (GC-MS) were performed. The liquid presented satisfactory results for the physico-chemical evaluations. Regarding the qualitative determination, it was possible to identify 49 compounds. Highlighting the phenols, with 44.90% of the number of compounds, mainly methoxyphenols. These are compounds with significant added value and industrial importance, indicating their use as raw material in the production of polymer resins, among other purposes.

NixZn1-xFe2O4 modified activated carbons from industrial waste as catalysts for hydrogen production

Abstract This study is aimed at the development of intelligent approach for clean energy production via valorization of industrial waste by-products. The proposed scheme is based on the preparation of activated carbon based catalysts for methanol decomposition as a source of hydrogen. Peach stones from the canning industry and by-products from low-rank coals treatment, all of them widely available in the Balkan region, are used as activated carbon precursors. The specific effect of carbon support on the formation of the loaded active NixZn1-xFe2O4 (x = 0; 0.2; 0.8; 1) ferrite phase are studied by nitrogen physisorption, XRD, HRTEM, FTIR, Moessbauer spectroscopy, TPR with hydrogen and Boehm method. To precise the discussion, analogues KIT-6 silica modifications are used as reference samples. It was found that the hosted in the activated carbon metal containing phase represents a complex mixture of Ni and/or Zn substituted magnetite, NiFe alloys, metallic Fe and ZnO. Its composition and dispersion is controlled by the variation of the Ni/Zn ratio and the texture peculiarities of the carbon support, the latter being easily tuned by the waste precursor used. The NixZn1-xFe2O4 modified activated carbons obtained from peach stones and coal treatment by-products possess a significant potential for sustainable environmental protection as cheap and effective catalysts for hydrogen production.

Modified peach stones by ethylenediamine as a new adsorbent for removal of Cr (VI) from wastewater

ABSTRACTThe potential of modified peach stone for Cr (VI) removal from wastewater was explored in this work. The properties of the materials were characterized by SEM, TGA, FT-IR, EDX and elemental analysis. It was found that 3 g/L EPS was good enough for removal of Cr (VI) in feed solution, with the maximum adsorption capacity was 24.68 mg/g. The pseudo-second-order kinetic model and Langmuir adsorption model was well fitted with adsorption data. In addition, EPS could be reused for sustainable operation for a number of cycles. All results confirm that EPS has potential for the removal of Cr (VI).

SYNTHESIS OF MAGNETIC ACTIVATED CARBONS FROM INDUSTRIAL WASTE

The application of magnetic particle technology has shown great potential to solve problems in advanced technological areas/fields. Materials which exhibit superparamagnetic behavior at room temperature are particularly interesting because, among other applications, they are able to adsorb molecules of interest from liquid or gaseous streams and could be separated through the use of a magnetic field. In this work, magnetic activated carbons (MACs) were prepared by the deposition of a magnetic phase onto the porous structure of an activated carbon (AC) obtained from industrial waste (peach stones). Different methods to introduce the magnetic phase onto the porous matrix were used. The variation on the textural properties of MAC in contrast with the corresponding AC, was evaluated from adsorption of nitrogen at 77K studies. The magnetic phase was identified by XRD and the surface chemical composition by EDS. The behavior of MACs under a variable external magnetic field (hysteresis cycle) and under a fixed external magnetic field, was analized.

Valorization of peach stones to high efficient activated carbon: Synthesis, characterization, and application for Cr(VI) removal from aqueous medium

ABSTRACTAgriculture residue (peach stones) was valorized to produce low-cost activated carbon. Granular peach stones were activated by H3PO4 after heating treatment. The peach stones activated carbon (PSAC) was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and nitrogen adsorption (BET).The simply prepared carbon was high-quality adsorbent with well-developed surface area and essentially microporous structure. PSAC was applied for Cr(VI) removal in batch system from aqueous solution. Cr(VI) removal was found 99.58% at pH 5.6. Investigations carried out proved that PSAC is an efficient and economic adsorbent for the treatment of toxic hexavalent chromium.

Modified peach stone shell powder for the removal of Cr (VI) from aqueous solution: synthesis, kinetic, thermodynamic, and modeling study

Citric acid treated peach (Prunus persica) stone shell as an effective adsorbent were synthesized for the adsorption of Cr (VI) from aqueous solutions. The aim of this study was to predict the optimal conditions for citric acid modification of peach kernel shell (CA-PSS) the modification process and the removal of Cr (VI) ions from aqueous solutions using a batch-type model. Research of its adsorption of Cr (VI) showed that CA-PSS in conditions at 120 °C for 4 h and in mass ratio of peach stone shell: citric acid =1:1 had greater adsorption capacity. Cr (VI) adsorption was investigated by changing several conditions. Adsorption studies have been carried out to determine the effect of time, pH, adsorbent dosage, temperature, and initial Cr (VI) ions concentration on the adsorption capacity of Cr (VI) ions by the esterified peach stone shell. The results indicate that the Langmuir model provides a better fit for the adsorption data. The equilibrium adsorption capacity of Cr (VI) was 25.71 mg/g for CA-PSS. The adsorption kinetic process followed the pseudo-second-order kinetics. Thermodynamic parameters such as the changes in ΔG°, ΔH°, and ΔS° have also been estimated, and the process was found to be spontaneous.

Peach stones valorizated to high efficient biosorbent for hexavalent chromium removal from aqueous solution: adsorption kinetics, equilibrium and thermodynamic studies

Peach stones valorizated to high efficient biosorbent for hexavalent chromium removal from aqueous solution: adsorption kinetics, equilibrium and thermodynamic studies

Archaeological evidence of early settlement in Venice: a comment on Ammerman et al. (2017)

Abstract

The Removal of Cr(VI) from Aqueous Solution by Activated Carbon Prepared from Apricot, Peach Stone and Almond Shell Mixture in a Fixed-Bed Column

The purpose of the study is to remove Cr(VI) from aqueous solutions in a fixed-bed column under different operating conditions [pH, influent Cr(VI) concentration, flow rate, bed height and temperature]. To this end, activated carbon prepared of apricot, peach stones and almond shell mixture was used. Adsorption capacity increased with the increase in bed height and influent Cr(VI) concentration, while it decreased with the increase in flow rate, pH and temperature. The adsorption capacity was found as 6.67 mg/g under optimum conditions. Adams–Bohart, Thomas and Yoon–Nelson models were applied to experimental data to find the kinetic parameters. It was determined that the appropriate model describing the adsorption mechanism was Thomas. As a result, the new activated carbon used in this study indicates its applicability in the removal of Cr(VI) ions in industrial wastewater.

Synthesis and characterization of high-quality activated carbons from hard-shelled agricultural wastes mixture by zinc chloride activation

In this study, a mixture apricot and peach stones, and almond shell, which are hard-shelled agricultural wastes, was evaluated as a precursor for activated carbon synthesis. Effects of the impregnation and pyrolysis conditions on ACs synthesis were investigated. The ACs were characterized by surface area, pore size, pore volume, surface functional groups by Boehm’s titration and FTIR analysis, ash content, pHpzc, and SEM-EDX. It has been found that the impregnation conditions and pyrolysis temperature have important effect on the microspores formation. ACs having specific surface area in the range of 1,125.73–2,073.04 m2g−1 and total pore volumes in the range of 0.5498–1.0918 cm3 g−1 can be synthesized from the mixture activated by ZnCl2 at impregnation ratios of higher than 15/40. These values are higher than those of the most commercial ACs. Therefore, it can be concluded that the mentioned wastes mixture is a promising precursor for producing high-quality ACs.

A comparative study on co-pyrolysis of lignocellulosic biomass with polyethylene terephthalate, polystyrene, and polyvinyl chloride: Synergistic effects and product characteristics

Co-pyrolysis of waste biomass and plastics was investigated to find out whether the quality of pyrolysis products was improved. For the sake of yield and compositional comparison, three polymers (polyethylene terephthalate, polystyrene, and polyvinyl chloride) and two biomasses (walnut shells and peach stones) were tested in a fixed bed reactor. The maximum bio-oil yield was obtained at 500 °C as 20.81 wt % for walnut shell and 18.30 wt %, for peach stone pyrolysis, then co-pyrolysis experiments were performed at 500 °C. Based on the experimental findings, blending of polyethylene terephthalate, polystyrene, and polyvinyl chloride into biomass affected product yield substantially. To gain more insight into the effect of polymers, liquid and solid products were analyzed by various analytical techniques. Results showed a significant modification on the chemical structure tars after co-pyrolysis, and tar yield increased up to 49.80 wt%. Meanwhile, modifying the structures and enhancing the quality of the tars and chars seemed possible by co-pyrolysis.

Fizičko-hemijske modifikacije otpadne biomase kao sredstvo poboljšanja sorpcionih svojstava materijala

Glavni konstituenti lignocelulozne (LC) biomase su lignin, celulozai hemiceluloza, kompleksni polimeri sa mnoštvom funkcionalnihgrupa koje je moguće modifikovati u cilju poboljšanjakarakteristika polaznog materijala. Ovaj rad prikazuje nekolikofizičkih i hemijskih modifikacija primenjenih na LC biomasu košticabreskve - KB (Prunus persica L.), otpada deponovanog nakonprerade voća u prehrambnoj industriji. Koštice KB najpre sumehanički aktivirane u dva tipa mlina, nakon čega je uslediohemijski tretman izabranog uzorka različitim agensima. Sorpcionieksperimenti izvedeni su u šaržnom reaktoru sa mešanjem nasobnoj temperaturi. Kinetika uklanjanja bakra, Cu(II), ispitivanaje primenom tri reakciona modela: model pseudo-prvog, pseudodrugogreda kao i Elovich-evog modela. Takođe su prikazane i FTIRanalize mehanički i hemijski tretiranih uzoraka.

CO2 gas-adsorption calorimetry applied to the study of chemically activated carbons

In this work, the microporous structure of a series of H3PO4 chemically activated carbons from peach stones with increased activation degree were investigated. CO2 Adsorption equilibrium isotherms and differential enthalpy curves were simultaneously measured at 300K using a Tian-Calvet microcalorimeter coupled to an adsorption manometric setup. Temperature programmed decomposition experiments were used to assess density of oxygen functional groups and determine the impact of surface chemistry on CO2 adsorption capacity. Computer based theoretical calculations were also performed to attempt to predict the adsorption enthalpy profiles. The most activated sample (Xp=0.90) has an average adsorption enthalpy which is approximately 8kJ/mol lower than that of the non-activated samples carbonized under the same conditions. The combination of techniques enabled a better understanding of the pore filling regimes with increasing coverage, since the use of CO2 as a probe gas allows accessing small pores, which otherwise would not be identified from N2 isotherms at 77K. The oxygen content on the carbon surface decreased almost 80% with the increasing degree of activation and did not influence in the CO2 adsorption. Besides providing information about carbon chemistry, CO2 adsorption calorimetry can also be successfully applied to the screening of carbons intended for CO2 capture.

Applicability of activated carbon obtained from peach stone as an electrochemical sensor for detecting caffeine

Simple, economical and highly sensitive electrodes for the detection of caffeine by using activated carbon from peach stones have been developed. The activated carbons were synthesized by chemical activation using ZnCl2 and ZnCl2:FeCl3 (1:1) as chemical agents, producing carbons with different textural properties and morphologies, which led to differences in the electroactive area of the materials that affected the electrochemical response to caffeine. The electrodes presented a linear response in the concentration range from 3.98 × 10−5 to 4.58 × 10−4 and 6.37 × 10−4 M for the carbon activated with ZnCl2 and ZnCl2:FeCl3 (1:1), respectively. The detection limits were estimated in 2.85 × 10−5 and 1.60 × 10−5 M. The electrodes were tested to measure caffeine in real life samples, giving caffeine concentrations close to the reported values. Despite presenting the lowest surface area and the lowest thermal stability, the activated carbon obtained with ZnCl2:FeCl3 (1:1) was more sensitive to caffeine, measuring caffeine concentrations very close to the reported values for the tested beverages. These results show that these electrodes may be an alternative to develop new and reliable analytical tools at low cost with high efficiency.

Adsorption of heavy metals and methylene blue from aqueous solution with citric acid modified peach stone

ABSTRACTPeach stones (PS) modified by citric acid (MPS) were used to remove heavy metals and methylene blue (MB) from wastewater. The effects of experimental factors such as pH, adsorbent dosage and contact time, etc. were conducted. Moreover, the adsorption kinetics and isotherm studies also were investigated. According to the Langmuir isotherm model, the maximum adsorption capacities of Pb2+, Cd2+, Cu2+ and MB were 118.76, 37.48, 32.22 and 178.25 mg/g, respectively. Finally, column experiments were also carried out to investigate the adsorption of Pb2+ and MB. All results indicated that PS has a good potential for the treatment of wastewater.

Activated carbon from Bulgarian peach stones as a support of catalysts for methanol decomposition

This study is aimed at the development of intelligent integrated scheme for full utilization of biomass for clean energy production. The proposed approach includes production of activated carbon based catalysts for methanol decomposition as a source of hydrogen, where both activated carbon and methanol, could be produced from biomass. In order to elucidate the impact of different activated carbon characteristics on the formation of the catalytic active phase, carbons with different texture and surface functionality are purposely obtained by changes in the activation temperature during the carbon preparation and its post-synthetic treatment with nitric acid. Peach stones, widely available in Bulgaria and Balkans region, are chosen as activated carbons precursor. Iron, zinc and ferrite modifications of thus obtained carbons are prepared by incipient wetness impregnation technique and nitrogen physisorption, XRD, HRTEM, UV-Vis, FTIR, Moessbauer spectroscopy, TPR with hydrogen and Boehm method are used for samples characterization. It is established that the state and catalytic activity of the supported metal oxide particles could be easily controlled by the procedure of the activated carbon preparation and this effect strongly depends on the nature of the loaded metal oxide. In case of iron modifications, the increase of the activation temperature during the carbon preparation promotes the formation of more finely dispersed, accessible for the reactants and active in methanol decomposition magnetite particles. The dispersion and the accessibility of the zinc oxide species in zinc modifications are improved by the formation of additional amount of surface acidic groups during the carbon pre-treatment with nitric acid. The combination of lower temperature of carbon activation with nitric acid pre-treatment promotes the formation of highly active ferrite nanoparticles in the binary modifications.

Exploring the activity of chemical-activated carbons synthesized from peach stones as metal-free catalysts for wet peroxide oxidation

Peach stones were used as raw material for the synthesis of activated carbons with different properties. Firstly, peach stones were chemically activated using a 12 M H3PO4 solution and carbonized under flowing air (400 °C). The obtained activated carbon, named as PS, is characterized by a high surface development (SBET = 1262 m2 g−1) and acidic character (pHPZC = 4.2). A fraction of PS was further carbonized under N2 atmosphere at 800 °C to remove surface functionalities and to increase its basicity (PS-800). In addition, a Pt catalyst supported on PS (3% w/w Pt/PS) was synthesized by incipient wetness impregnation, resulting in a considerable hydrophilicity increasing. The synthesized materials were tested in the catalytic wet peroxide oxidation (CWPO) of highly concentrated solutions of 4-nitrophenol (4-NP, 5 g L−1) during 24 h experiments, conducted at relatively mild operating conditions (T = 50–110 °C, pH = 3, catalyst load = 2.5 g L−1 and [H2O2]0 = 17.8 g L−1, corresponding to the stoichiometric amount of H2O2 needed for the complete mineralization of 4-NP). It was observed that the increase of electron-donating functionalities in PS-800 promotes the generation of reactive HO radicals, being the activity towards CWPO twice higher than that obtained with the pristine PS. Besides, increasing operating temperature substantially enhances CWPO, finding a 80% of 4-NP removal at 110 °C. On the other hand, despite the sharp increment in H2O2 decomposition due to the presence of Pt particles in Pt/PS catalyst, this decomposition is inefficient in all cases, with a consequent poor pollutant removal. This can be attributed to the recombination of HO radicals into non-reactive species −scavenging effects, promoted by the hydrophilicity of the catalyst.

Venice gains years of history

Deep beneath the mosaic floor of Venice's St Mark's Basilica, archaeologists have found two 1300-year-old peach stones. They add at least 100 years to the city's history. Most of Italy's great cities date back to the Romans, but not Venice, says Albert Ammerman at Colgate University in Hamilton NY. There were Romans on Torcello island in the north of the Venetian lagoon, but there are no Roman remains in Venice. Instead, the city's history seems to begin in the 9th century.

Beneath the Basilica of San Marco: new light on the origins of Venice

Abstract