Induced changes of pyrolysis temperature on the physicochemical traits of sewage sludge and on the potential ecological risks

Souza, Claudineia de Souza; Bomfim, Marcela Rebouças; Almeida, Maria da Conceição de; Alves, Lucas de Souza; Santana, Welder Neves de; Amorim, Itamar Carlos da Silva; Santos, Jorge Antônio Gonzaga

doi:10.1038/s41598-020-79658-4

Cited by 25 publications

(11 citation statements)

References 75 publications

(59 reference statements)

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“…Typically, activated carbon can be synthesized from a variety of carbonaceous materials including cherry stone [ 4 ], sugar cane bagasse [ 5 ], palm stone [ 6 ], agricultural waste [ 7 ], hemp stem hemicellulose [ 8 ], and bamboo [ 9 , 10 ] or coal [ 11 ], lignite [ 12 ], and peat [ 13 ]. Sewage sludge, the residual material produced as a by-product from sewage treatment plants and which contains large amounts of organic matter, could be another potential source for activated carbon production, since the biochar produced from the sewage sludge showed a reasonably high carbon content and surface area of 47% and 152 m 2 /g, respectively [ 14 , 15 ]. The elementary structures of activated carbon are graphene layers and quasi-graphitic fragments that are composed together, which are referred to as microcrystalline structures.…”

Section: Introductionmentioning

confidence: 99%

The Analysis of Pore Development and Formation of Surface Functional Groups in Bamboo-Based Activated Carbon during CO2 Activation

2021

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Pore development and the formation of oxygen functional groups were studied for activated carbon prepared from bamboo (Bambusa bambos) using a two-step activation with CO2, as functions of carbonization temperature and activation conditions (time and temperature). Results show that activated carbon produced from bamboo contains mostly micropores in the pore size range of 0.65 to 1.4 nm. All porous properties of activated carbons increased with the increase in the activation temperature over the range from 850 to 950 °C, but decreased in the temperature range of 950 to 1000 °C, due principally to the merging of neighboring pores. The increase in the activation time also increased the porous properties linearly from 60 to 90 min, which then dropped from 90 to 120 min. It was found that the carbonization temperature played an important role in determining the number and distribution of active sites for CO2 gasification during the activation process. Empirical equations were proposed to conveniently predict all important porous properties of the prepared activated carbons in terms of carbonization temperature and activation conditions. Oxygen functional groups formed during the carbonization and activation steps of activated carbon synthesis and their contents were dependent on the preparation conditions employed. Using Boehm’s titration technique, only phenolic and carboxylic groups were detected for the acid functional groups in both the chars and activated carbons in varying amounts. Empirical correlations were also developed to estimate the total contents of the acid and basic groups in activated carbons in terms of the carbonization temperature, activation time and temperature.

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Section: Introductionmentioning

confidence: 99%

The Analysis of Pore Development and Formation of Surface Functional Groups in Bamboo-Based Activated Carbon during CO2 Activation

2021

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“…Specifically, the yield, surface area, and pore structure was known to improve with the inherent minerals present in the sludge samples due to the improvements in metal catalyzed thermochemical reactions during pyrolysis [ 28 ]. Furthermore, another study concluded that the increase in pyrolysis temperature is known to increase surface area and stabilize the toxic metals present hence reducing the likelihood of leaching [ 29 ]. Hence, the produced char is considered low risk for the environment due to less bioavailability and decreased leaching capacity [ 30 ].…”

Section: Co-pyrolysis and Potential Chars For Water Treatmentmentioning

confidence: 99%

A review of prospects and current scenarios of biomass co-pyrolysis for water treatment

Zuhara

Mackey

Al‐Ansari

et al. 2022

Biomass Conv. Bioref.

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With ever-growing population comes an increase in waste and wastewater generated. There is ongoing research to not only reduce the waste but also to increase its value commercially. One method is pyrolysis, a process that converts wastes, at temperatures usually above 300 °C in a pyrolysis unit, to carbon-rich biochars among with other useful products. These chars are known to be beneficial as they can be used for water treatment applications; certain studies also reveal improvements in the biochar quality especially on the surface area and pore volume by imparting thermal and chemical activation methods, which eventually improves the uptake of pollutants during the removal of inorganic and organic contaminants in water. Research based on single waste valorisation into biochar applications for water treatment has been extended and applied to the pyrolysis of two or more feedstocks, termed co-pyrolysis, and its implementation for water treatment. The co-pyrolysis research mainly covers activation, applications, predictive calculations, and modelling studies, including isotherm, kinetic, and thermodynamic adsorption analyses. This paper focuses on the copyrolysis biochar production studies for activated adsorbents, adsorption mechanisms, pollutant removal capacities, regeneration, and real water treatment studies to understand the implementation of these co-pyrolyzed chars in water treatment applications. Finally, some prospects to identify the future progress and opportunities in this area of research are also described. This review provides a way to manage solid waste in a sustainable manner, while developing materials that can be utilized for water treatment, providing a double target approach to pollution management.

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“…When oxygen was limited during the 600 • C heat treatment, N leaching was eliminated entirely. Oxygen limitation likely sequestered N via formation of biochar, volatilizing N compounds, and forming stable aromatic compounds [51].…”

Section: Nitrogen Desorptionmentioning

confidence: 99%

Washing and Heat Treatment of Aluminum-Based Drinking Water Treatment Residuals to Optimize Phosphorus Sorption and Nitrogen Leaching: Considerations for Lake Restoration

Huser

Padungthon

Junggoth

et al. 2021

Water

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Drinking water treatment residuals (DWTRs) generated during drinking water treatment have been proposed for use in lake restoration as a solid-phase sorbent to inactivate phosphorus (P) in lake sediment. However, treatments that minimize leaching of nitrogen (N) and optimize P sorption capacity may be necessary prior to use. This study assessed seven different treatment methods, including washing and heat treatments at different temperatures and with and without oxygen limitation, among two DWTRs from Thailand. Results showed that oxygen-limited heat treatment at 600 °C substantially reduced N leaching (<0.2 mg/kg TKN) while also improving P sorption capacity (increase of 18–32% compared to untreated DWTR) to a maximum of 45.7 mg P/kg. Washing with deionized water reduced N leaching if a sufficient volume was used but did not improve P sorption. Heating at 200 °C with or without the presence of oxygen did not improve N leaching or P sorption. Regression of P sorption parameters from a two-surface Langmuir isotherm against physio-chemical properties indicated that oxalate-extractable (i.e., amorphous) aluminum and iron were significantly associated with total P sorption capacity (R2 = 0.94), but micropores and oxalate-extractable P modulated the P sorption from high-affinity to low-affinity mechanisms. In conclusion, this study confirmed the importance of amorphous aluminum in DWTRs for inactivating P, and the results suggest that high-temperature treatment under oxygen-limited conditions may be the most reliable way to optimize DWTRs for environmental remediation applications.

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Induced changes of pyrolysis temperature on the physicochemical traits of sewage sludge and on the potential ecological risks

Cited by 25 publications

References 75 publications

The Analysis of Pore Development and Formation of Surface Functional Groups in Bamboo-Based Activated Carbon during CO2 Activation

The Analysis of Pore Development and Formation of Surface Functional Groups in Bamboo-Based Activated Carbon during CO2 Activation

A review of prospects and current scenarios of biomass co-pyrolysis for water treatment

Washing and Heat Treatment of Aluminum-Based Drinking Water Treatment Residuals to Optimize Phosphorus Sorption and Nitrogen Leaching: Considerations for Lake Restoration

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