scholarly journals The Effect of Biodegradable Waste Pyrolysis Temperatures on Selected Biochar Properties

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1644
Author(s):  
Katarzyna Wystalska ◽  
Anna Kwarciak-Kozłowska
Keyword(s):  
Surface Area ◽  
Functional Groups ◽  
Pyrolysis Temperature ◽  
Beech Wood ◽  
Wood Chips ◽  
Walnut Shell ◽  
Surface Functional Groups ◽  
Biodegradable Waste ◽  
Wide Range ◽  
Rye Straw

Biochars produced during biodegradable waste pyrolysis are products with a wide range of environmental applications. The effect of impact biochars depends on their properties which determine the course of specific processes. The main aim of the study was to investigate the effect of pyrolysis temperature on selected properties of biochar produced from various plant wastes (beech wood chips, walnut shells, wheat-rye straw), the valorization of which is of key importance for the implementation of the circular economy. Biochars were produced at temperatures of: 400 °C, 500 °C, 600 °C and 700 °C in a nitrogen atmosphere. An increase in the pyrolysis temperature caused a drop in the biochar production yield. As the temperature increased, higher carbon content and lower hydrogen content could be seen in the products obtained. An increase in the pH and total organic carbon (TOC) values also found. The influence of temperature on ash content, observed in the case of BWS (biochar from walnut shell) and BWRS (biochar from wheat and rye straw), did not occur in the case of BWC (biochar from beech wood chips). Another parameter that demonstrated a growing tendency with increasing temperature was the BET specific surface area (except for biochars from wheat and rye straw). An increase in pyrolysis temperature caused a decrease in the diversity and density of the surface functional groups of biochars. The influence of the type of precursor used in the production of biochar on the presence of surface functional groups was demonstrated. The presence of intense stretching vibrations of C–O bonds, having a potential impact on the sorption capacity of biochars, was determined in the FTIR spectra of BWC600 and BWC700 biochars, this feature, combined with the large BET surface area, may affect the sorption potential of these biochars. The presence of this type of high-intensity vibrations was also observed in the spectra of biochar BWRS600 and BWRS700. This can compensate for the low BET surface value and play an important role when using these biochars in sorption processes for organic and inorganic compounds.

scholarly journals Bio-polishing sludge adsorbents for dye removal

2016 ◽  
Vol 18 (4) ◽  
pp. 15-21 ◽  
Author(s):  
Muhammad Abbas Ahmad Zaini ◽  
Norulaina Alias ◽  
Mohd. Azizi Che Yunus
Keyword(s):  
Methylene Blue ◽  
Specific Surface ◽  
Surface Area ◽  
Functional Groups ◽  
Specific Surface Area ◽  
Treatment Strategies ◽  
Blue Dye ◽  
Surface Functional Groups ◽  
Adsorption Capacities ◽  
Maximum Removal

Abstract The objective of this work is to evaluate the removal of methylene blue dye by bio-polishing sludge-based adsorbents. The adsorbents were characterized according to the specific surface area, pH upon the treatment and surface functional groups. The adsorption of dye was carried out at room temperature, and the adsorption data were analyzed using the isotherm and kinetics models. The bio-polishing sludge is rich in ash content, and the presence of surface functional groups varied with the treatment strategies. The specific surface area of adsorbents is between 7.25 and 20.8 m2/g. Results show that the maximum removal of methylene blue by sludge adsorbents was observed to have the following order: untreated sludge (SR) > zinc chloride-treated (SZ) > microwave-dried (SW) = potassium carbonate-treated (SK) > acid-washed (SH). The maximum adsorption capacities for SR and SZ as predicted by the Langmuir model are 170 and 135 mg/g, respectively. Although SR demonstrates a higher maximum removal than SZ, the latter exhibits greater removal intensity and rate constant even at high dye concentration. The bio-polishing sludge is a promising adsorbent for dye wastewater treatment.

scholarly journals The importance of surface functional groups in the adsorption of copper onto walnut shell derived activated carbon

2017 ◽  
Vol 76 (11) ◽  
pp. 3022-3034 ◽  
Author(s):  
Ruzhen Xie ◽  
Yan Jin ◽  
Yao Chen ◽  
Wenju Jiang
Keyword(s):  
Activated Carbon ◽  
Functional Groups ◽  
Photoelectron Spectroscopy ◽  
Chemical Activation ◽  
Critical Role ◽  
Walnut Shell ◽  
Infrared Spectrometry ◽  
Copper Uptake ◽  
Surface Functional Groups ◽  
Copper Adsorption

Abstract In this study, activated carbon (AC) was prepared from walnut shell using chemical activation. The surface chemistry of the prepared AC was modified by introducing or blocking certain functional groups, and the role of the different functional groups involved in the copper uptake was investigated. The structural and chemical heterogeneity of the produced carbons are characterized by Fourier transform infrared spectrometry, X-ray photoelectron spectroscopy, Boehm titration method and N2/77 K adsorption isotherm analysis. The equilibrium and the kinetics of copper adsorption onto AC were studied. The results demonstrated that the functional groups on AC played an important role in copper uptake. Among various surface functional groups, the oxygen-containing group was found to play a critical role in the copper uptake, and oxidation is the most effective way to improve Cu (II) adsorption onto AC. Ion-exchange was identified to be the dominant mechanism in the copper uptake by AC. Some other types of interactions, like complexation, were also proven to be involved in the adsorption process, while physical force was found to play a small role in the copper uptake. The regeneration of copper-loaded AC and the recovery of copper were also studied to evaluate the reusability of the oxidized AC.

Surface functional groups and defects on carbon nanotubes affect adsorption–desorption hysteresis of metal cations and oxoanions in water

2014 ◽  
Vol 1 (5) ◽  
pp. 488-495 ◽  
Author(s):  
Jie Li ◽  
Changlun Chen ◽  
Shouwei Zhang ◽  
Xiangke Wang
Keyword(s):  
Carbon Nanotubes ◽  
Specific Surface ◽  
Surface Area ◽  
Functional Groups ◽  
Metal Ion ◽  
Ion Adsorption ◽  
Surface Functional Groups ◽  
Metal Ion Adsorption ◽  
Desorption Hysteresis ◽  
Adsorption Desorption

This study probed the effects of functional groups, specific surface area and defects on metal ion adsorption and desorption.

scholarly journals Biochar surface functional groups as affected by biomass feedstock, biochar composition and pyrolysis temperature

2021 ◽  
Vol 4 ◽  
pp. 36-46
Author(s):  
Rainer Janu ◽  
Verena Mrlik ◽  
Doris Ribitsch ◽  
Jakub Hofman ◽  
Petr Sedláček ◽  
...  
Keyword(s):  
Functional Groups ◽  
Pyrolysis Temperature ◽  
Biomass Feedstock ◽  
Surface Functional Groups

scholarly journals Coffee residue-based activated carbons for phenol removal

2021 ◽  
Author(s):  
Hemavathy Palanisami ◽  
Mohamad Rafiuddin Mohd Azmi ◽  
Muhammad Abbas Ahmad Zaini ◽  
Zainul Akmar Zakaria ◽  
Muhd Nazrul Hisham Zainal Alam ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Surface Area ◽  
Functional Groups ◽  
High Performance ◽  
Activated Carbons ◽  
Phenol Removal ◽  
Surface Functional Groups ◽  
Maximum Capacity ◽  
Second Stage ◽  
Adsorptive Properties

Abstract This work was aimed to evaluate the adsorptive properties of activated carbons from coffee residue for phenol removal. The coffee residue was activated using H3PO4 and KOH, and the resultant activated carbons were characterized for surface area and functional groups. The values of surface area were recorded as 1,030 m2/g and 399 m2/g for H3PO4- and KOH-activated carbons, respectively. The maximum capacity for phenol removal is comparable for both activated carbons at 43 mg/g. The pores might be inaccessible due to electrostatic repulsion by surface functional groups and hydroxyl anions. The second stage in a two-stage adsorber design is necessary to accomplish the process with high performance and minimum dosage of activated carbon. Coffee residue is a promising activated carbon precursor for phenol removal.

scholarly journals Changes in the physicochemical characteristics of peanut straw biochar after freeze-thaw and dry-wet aging treatments of the biomass

BioResources ◽  
2019 ◽  
Vol 14 (2) ◽  
pp. 4329-4343
Author(s):  
Yongqiang Cao ◽  
Yande Jing ◽  
Hao Hao ◽  
Xuan Wang
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Functional Groups ◽  
Specific Surface Area ◽  
Pyrolysis Temperature ◽  
Ph Value ◽  
Aging Treatment ◽  
Physicochemical Characteristics ◽  
Freeze Thaw ◽  
Peanut Straw

Effects of aging after pyrolysis were tested relative to the physicochemical characteristics of peanut straw biochar. Biochar was prepared at pyrolysis temperatures of 350 °C, 500 °C, and 650 °C; then, it was freeze-thawed and dry-wet aged. The physicochemical characteristics of the fresh and aged biochar were analyzed. The results showed that the pyrolysis temperature, ambient temperature, and humidity affected the physicochemical characteristics of the biochar. With the increase of pyrolysis temperature, the yield and surface acidic functional groups of the fresh biochar decreased, whereas the ash content, C content, pH, specific surface area, and mesoporous volume of the fresh biochar increased. The aging treatment increased the acidic functional groups content in the biochar and reduced the aromatic functional groups content, which decreased the pH value of the biochar. The aging treatment increased the specific surface area and pore volume of the biochar, and the effect of freeze-thaw aging was greater than that of dry-wet aging. The aging treatment also destroyed the complete shape of the fresh biochar, and reduced its stability. After the aging treatment, the C content of the biochar decreased, whereas the O content increased, due to oxidation of the biochar.

scholarly journals Surface Functionalization of Biochar from Oil Palm Empty Fruit Bunch through Hydrothermal Process

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 149
Author(s):  
Izzudin Ibrahim ◽  
Toshiki Tsubota ◽  
Mohd Ali Hassan ◽  
Yoshito Andou
Keyword(s):  
Surface Area ◽  
Functional Groups ◽  
Oil Palm ◽  
Large Scale ◽  
Hydrothermal Process ◽  
Real Life ◽  
Bet Surface Area ◽  
Empty Fruit Bunch ◽  
Surface Functional Groups ◽  
Adsorption Performance

The use of biochar as an adsorbent for wastewater treatment purposes has been hindered due to its lower surface area compared to activated carbon. Current research on increasing surface functional groups on biochar surfaces to improve its adsorption performance suggests using high chemical concentration and long period of modification. This study solves these problems by focusing on improving surface functionalities of biochar via the hydrothermal functionalization process. Oil palm empty fruit bunch biochar was functionalized using autoclave with nitric acid as the functionalization agent. Functionalized biochar properties such as Brunauer–Emmett–Teller (BET) surface area and surface functional groups were analyzed and compared with untreated biochar. Fourier Transform Infrared (FTIR) spectroscopic analysis shows a significant increase in absorption by oxygen functional groups and is corroborated with energy dispersive X-ray (EDX) analysis. The process does not result in any major change in surface morphology and reduction in surface area value. Methylene blue (MB) adsorption test shows 7 times increase in adsorption performance. These results show that the simple hydrothermal functionalization process successfully functionalizes the biochar surface and improves its performance without affecting its surface area at lower concentration, and shorter time compared to previous studies. This result, with future large-scale experimentation using real-life equipment in palm oil mills, would provide a better technology that can be implemented in the industry.

Study of Characteristic of Vetiver Fiber Before and after Alkaline Treatment

2010 ◽  
Vol 123-125 ◽  
pp. 1191-1194 ◽  
Author(s):  
Wimonlak Sutapun ◽  
Nitinat Suppakarn ◽  
Yupaporn Ruksakulpiwat
Keyword(s):  
Thermogravimetric Analysis ◽  
Specific Surface ◽  
Surface Area ◽  
Functional Groups ◽  
Surface Analysis ◽  
Alkaline Treatment ◽  
X Ray Diffraction ◽  
Surface Functional Groups ◽  
X Ray ◽  
Before And After

In this study, untreated and alkali-treated vetiver fibers were characterized by thermogravimetric analysis, BET surface analysis, X-ray diffraction and FTIR (ATR) microspectroscopy,. It was revealed that the alkaline treatment influenced properties of vetiver fiber. By the treatment, some hemicellulose and lignin were removed, resulting in higher decomposition temperatures. In addition, the specific surface area were decreased, and crystalline structure was altered. However, no evidence of changes in surface functional groups was observed.

scholarly journals Development and Characterization of Composite Carbon Adsorbents with Photocatalytic Regeneration Ability: Application to Diclofenac Removal from Water

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 173
Author(s):  
Velma Beri Kimbi Yaah ◽  
Satu Ojala ◽  
Hamza Khallok ◽  
Tiina Laitinen ◽  
Marcin Selent ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Functional Groups ◽  
Specific Surface Area ◽  
Palm Kernel ◽  
Hydrothermal Carbonization ◽  
Carbon Composite ◽  
Carbon Adsorbents ◽  
Regeneration Ability ◽  
Activation Temperature

This paper presents results related to the development of a carbon composite intended for water purification. The aim was to develop an adsorbent that could be regenerated using light leading to complete degradation of pollutants and avoiding the secondary pollution caused by regeneration. The composites were prepared by hydrothermal carbonization of palm kernel shells, TiO2, and W followed by activation at 400 °C under N2 flow. To evaluate the regeneration using light, photocatalytic experiments were carried out under UV-A, UV-B, and visible lights. The materials were thoroughly characterized, and their performance was evaluated for diclofenac removal. A maximum of 74% removal was observed with the composite containing TiO2, carbon, and W (HCP25W) under UV-B irradiation and non-adjusted pH (~5). Almost similar results were observed for the material that did not contain tungsten. The best results using visible light were achieved with HCP25W providing 24% removal of diclofenac, demonstrating the effect of W in the composite. Both the composites had significant amounts of oxygen-containing functional groups. The specific surface area of HCP25W was about 3 m2g−1, while for HCP25, it was 160 m2g−1. Increasing the specific surface area using a higher activation temperature (600 °C) adversely affected diclofenac removal due to the loss of the surface functional groups. Regeneration of the composite under UV-B light led to a complete recovery of the adsorption capacity. These results show that TiO2- and W-containing carbon composites are interesting materials for water treatment and they could be regenerated using photocatalysis.

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