“…The presence of hydrogen peroxide triggers the oxidation/destabilization of anionic substances avoiding the undesirable repulsion between particles. This was partially experienced by Liu and coworkers (Liu et al 2022a ) in the range of temperatures 135–170 °C. Fig.…”
Section: Resultsmentioning
confidence: 92%
“…Municipal sewage sludge has been used as a raw material to produce carbon-based adsorbents for the adsorption of several contaminants in water such as heavy metals (Koetlisi and Muchaonyerwa 2019 ; Ngambia et al 2019 ; Rezai and Allahkarami 2021 ), dyes (Chen et al 2021 ), pesticides (Sanz-Santos et al 2022 ; Zhang et al 2021 ), phenols (Kou et al 2021 ), polycyclic aromatic hydrocarbons (Godlewska et al 2019 ), and pharmaceuticals (Ding et al 2012 ; Yin et al 2019 ). Also, some works in the literature report the use of activated sludge as a raw substance to produce biochar for CO 2 capture (Liu et al 2022a ; Liu et al 2022b ).…”
The excess of activated sludge generated in municipal wastewater treatment plants constitutes one of the challenging problems facing modern society. The high-water content of this waste makes difficult the transport, disposal, and management of these solids. In this work, activated sludge excess from a secondary clarifier has been dehydrated by means of a combination of temperature and hydrogen peroxide treatment. Three main operating variables have been considered to affect sludge dewaterability and filterability. Temperature (120–180 °C), hydrogen peroxide dose (0.01–0.03 M), and treatment time (20–60 min) influence have been assessed by completing a 15-run Box Behnken experimental design. Different output variables (water content, resistance to filtration, sedimentation volumetric index, extracellular polymeric substances, etc.) have been monitored. Generally, temperature seems to be the most influencing parameter to obtain a dehydrated sludge with acceptable management/disposal characteristics (sludge volume reduction and filterability). In line with the concept of circular economy, an attempt has been conducted to obtain a sustainable biosorbent from the dehydrated sludge generated in the previous stage. Optimum conditions of carbonization and activation revealed that the solid obtained at 400 °C by using ammonium nitrate as activation agent was the most efficient absorbent to eliminate some model compounds from water (namely, phenol, ofloxacin, and diuron); however, a clear improvement margin in the synthesis is foreseen.
“…The presence of hydrogen peroxide triggers the oxidation/destabilization of anionic substances avoiding the undesirable repulsion between particles. This was partially experienced by Liu and coworkers (Liu et al 2022a ) in the range of temperatures 135–170 °C. Fig.…”
Section: Resultsmentioning
confidence: 92%
“…Municipal sewage sludge has been used as a raw material to produce carbon-based adsorbents for the adsorption of several contaminants in water such as heavy metals (Koetlisi and Muchaonyerwa 2019 ; Ngambia et al 2019 ; Rezai and Allahkarami 2021 ), dyes (Chen et al 2021 ), pesticides (Sanz-Santos et al 2022 ; Zhang et al 2021 ), phenols (Kou et al 2021 ), polycyclic aromatic hydrocarbons (Godlewska et al 2019 ), and pharmaceuticals (Ding et al 2012 ; Yin et al 2019 ). Also, some works in the literature report the use of activated sludge as a raw substance to produce biochar for CO 2 capture (Liu et al 2022a ; Liu et al 2022b ).…”
The excess of activated sludge generated in municipal wastewater treatment plants constitutes one of the challenging problems facing modern society. The high-water content of this waste makes difficult the transport, disposal, and management of these solids. In this work, activated sludge excess from a secondary clarifier has been dehydrated by means of a combination of temperature and hydrogen peroxide treatment. Three main operating variables have been considered to affect sludge dewaterability and filterability. Temperature (120–180 °C), hydrogen peroxide dose (0.01–0.03 M), and treatment time (20–60 min) influence have been assessed by completing a 15-run Box Behnken experimental design. Different output variables (water content, resistance to filtration, sedimentation volumetric index, extracellular polymeric substances, etc.) have been monitored. Generally, temperature seems to be the most influencing parameter to obtain a dehydrated sludge with acceptable management/disposal characteristics (sludge volume reduction and filterability). In line with the concept of circular economy, an attempt has been conducted to obtain a sustainable biosorbent from the dehydrated sludge generated in the previous stage. Optimum conditions of carbonization and activation revealed that the solid obtained at 400 °C by using ammonium nitrate as activation agent was the most efficient absorbent to eliminate some model compounds from water (namely, phenol, ofloxacin, and diuron); however, a clear improvement margin in the synthesis is foreseen.
“…Properties of biochar such as surface area, porosity and surface functional groups need to be further improved to enhance CO 2 capture (Liu et al 2022) Thereby, surface modi cation and grafting of functional groups onto the surface of the material may be an effective approach to improve the adsorption performance of biochar toward CO 2 adsorption. Adio et al (2020) used nitrogen modi cation to alter the surface porous carbon derived from sugarcane bagasse for CO 2 capture.…”
Environmental problems such as climate change and global warming caused by greenhouse gases, mainly CO 2, have become a worldwide topic of concern. Adsorption is a promising method for CO 2 capture. In this research, a series of amine functionalized on biochar based desiccated coconut waste (amine-biochar@DCW) namely ethylenediamine functionalized biochar@DCW (EDA-biochar@DCW), diethylenetriamine functionalized biochar@DCW (DETA-biochar@DCW), triethylenetetramine functionalized biochar@DCW (TETA-biochar@DCW), tetraethylenepentamine functionalized biochar@DCW (TEPA-biochar@DCW), and pentaethylenehexamine functionalized biochar@DCW (PEHAbiochar@DCW) adsorbents were synthesized and characterized. From the characterization analyses, series of amine-biochar@DCW adsorbents had better developed pore structure and larger speci c surface area than that of pristine desiccated coconut waste (DCW). Furthermore, the results showed that the increase percentage of elemental of C and N as well the presence peaks NH stretching, NH bending, CN stretching, and CN bending, revealing the presence of amine on the surface of biochar@DCW. From the CO 2 adsorption experiment, among amine modi ed biochar adsorbents, TETA-biochar@DCW had higher CO 2 adsorption capacity (61.78 mg/g) with mass ratio (m:m) of biochar@DCW:TETA (1:2). The adsorption kinetics on the TETA-biochar@DCW was best tted by the pseudo-second model, suggesting the adsorption process occurs through chemisorption. Additionally, TETA-biochar@DCW depicts high selectivity towards CO 2 gas and good reusability after ve CO 2 adsorption-desorption cycles.
“…Biochar is a cost-effective and easily obtainable material with a large specific surface area, high pore size, and abundant functional groups [3]. It can be added as an additive to anaerobic fermentation systems to mitigate ammonia-nitrogen inhibition and acidification, thereby improving gas production rates and maintaining system stability [4].…”
Anaerobic fermentation technology is a sustainable method for treating organic waste. However, the process can be hindered by low gas production, system instability due to acidification, ammonianitrogen inhibition, and microorganisms. The addition of biochar to the anaerobic fermentation system can improve gas production rates and maintain system stability. This paper summarizes the research progress on the effect of biochar on anaerobic fermentation systems by discussing the preparation and characteristics of biochar, its main effects on anaerobic fermentation systems, Exploring the potential for further research and in-depth application of biochar in anaerobic fermentation systems.
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