Sludge-derived biochar: Physicochemical characteristics for environmental remediation

The global production of fecal wastes is envisioned to reach a very high tonnage by 2030. Perilous handling and consequential exposition of human and animal fecal matter are inextricably linked with stunted growth, enteric diseases, inadequate cognitive skills, and zoonoses. Sludge treatment from sewage and water treatment processes accounts for a very high proportion of overall operational expenditure. Straightforward carbonization of sludges to generate biochar adsorbents or catalysts fosters a circular economy, curtailing sludge processing outlay. Biochars, carbonaceous substances synthesized via the thermochemical transformation of biomass, possess very high porosity, cation exchange capacity, specific surface area, and active functional sorption sites making them very effective as multifaceted adsorbents, promoting a negative carbon emission technology. By customizing the processing parameters and biomass feedstock, engineered biochars possess discrete physicochemical characteristics that engender greater efficaciousness for adsorbing various contaminants. This review provides explicit insight into the characteristics, environmental impact considerations, and SWOT analysis of different sludges (drinking water, fecal, and raw sewage sludge) and the contemporary biochar production, modification, characterization techniques, and physicochemical characteristics, factors influencing the properties of biochars derived from the aforestated sludges, along with the designing of chemical reactors involved in biochar production. This paper also manifests a state-of-the-art discussion of the utilization of sludge-derived biochars for the eviction of toxic metal ions, organic compounds, microplastics, toxic gases, vermicomposting approaches, and soil amelioration with an emphasis on biochar recyclability, reutilization, and toxicity. The practicability of scaling up biochar generation with multifaceted, application-accustomed functionalities should be explored to aggrandize socio-economic merits

Application of neural network in metal adsorption using biomaterials (BMs): a review

With growing environmental consciousness, biomaterials (BMs) have garnered attention as sustainable materials for the adsorption of hazardous water contaminants. These BMs are engineered using surface treatments or physical alterations to enhance their adsorptive properties. The lab-scale methods generally employ a One Variable at a Time (OVAT) approach to analyze the impact of biomaterial modifications, their characteristics and other process variables such as pH, temperature, dosage, etc., on the removal of metals via adsorption. Although implementing the adsorption procedure using BMs seems simple, the conjugate effects of adsorbent properties and process attributes implicate complex nonlinear interactions. As a result, artificial neural networks (ANN) have gained traction in the quest to understand the complex metal adsorption processes on biomaterials, with applications in environmental remediation and water reuse. This review discusses recent progress using ANN frameworks for metal adsorption using modified biomaterials. Subsequently, the paper comprehensively evaluates the development of a hybrid-ANN system to estimate isothermal, kinetic and thermodynamic parameters in multicomponent adsorption systems

Emerging towards zero carbon footprint via carbon dioxide capturing and sequestration

Concerns about climatic changes and global temperature enhancements have sparked efforts worldwide to curb the magnitude of atmospheric carbon dioxide. A key tactic for achieving carbon dioxide emission mitigation goals is Carbon dioxide capturing and sequestration, which is critical for the seamless changeover from the prevailing fossil-based power systems to more eco-friendly future energy systems. Among the carbon dioxide capturing techniques, post-combustion capture is the most practical method for retrofitting existing power plants although it result with 3–15 vol.% concentrated carbon dioxide gas stream. Chemical looping combustion capturing receives much attention receives much attention owing to its non-pollution nature and the yielding of highly concentrated carbon dioxide stream, up to 100%. This review also explores a variety of sequestration strategies, including geological carbon dioxide sequestration with multiple geological carbon dioxide storage sinks, mineral carbonation sequestration, as well as marine sequestration. The carbon dioxide transportation and the storage facilities comprising pressure vessels, pipelines, and cryogenic storage tanks are also discussed briefly. The Enhanced gas recovery, Enhanced water recovery, and Enhanced oil recovery, which rely on geologically stored carbon dioxide are also taken into account in this analysis as a part of the commercial-economic application of carbon dioxide capturing and sequestration. Along with the risk considerations related to the sequestration processes, the efficient exploitation of the sequestered carbon dioxide is delineated as a road map leading to future prospects. Concerns have been raised that the widespread adoption of carbon dioxide capturing and sequestration will likely be affected by the general public perceptions due to unawareness, along with potential leakage risks and the enormous capturing cost, which should be puzzled out for the effective uptake of carbon dioxide capturing and sequestration strategies

Relevance of wood biochar on CO2 adsorption: A review

Anthropogenic CO2 emissions are indeed escalating as a consequence of the expanding global energy demand, emphasizing the significance of CO2 capture, where carbon capture and sequestration have been deemed to be the most efficacious approach for alleviating CO2 emissions. Multiple technologies have been devised to capture CO2, and current research is primarily aimed at improving CO2 adsorption on wood biochar, a carbonaceous substance derived from wood-based feedstock. Activation, metal doping, and surface group functionalization are some of the modification strategies being ultimately employed to enhance the adsorbent's effectiveness. The review also provides an insight into various Wood biochar production techniques moreover the adsorbent effectiveness assessment through a variety of isotherm and kinetic modeling techniques is also incorporated. This study summarizes different parameters like specific surface area (0.01- 1408.8 ​m2/g), pore volume (0.1-0.85 ​cm3/g), ash content (2.02-48.0%), and functional groups that stand as criteria for evaluating the adsorption ability of biochar. The CO2-adsorbed wood biochar employment as a sort of soil enhancer, feedstock material for biofuel, as well as the technique for warming up the building basement during frigid climates, is delineated as a roadmap leading to future aspects

Sludge-derived biochar: Physicochemical characteristics for environmental remediation

The global production of fecal wastes is envisioned to reach a very high tonnage by 2030. Perilous handling and consequential exposition of human and animal fecal matter are inextricably linked with stunted growth, enteric diseases, inadequate cognitive skills, and zoonoses. Sludge treatment from sewage and water treatment processes accounts for a very high proportion of overall operational expenditure. Straightforward carbonization of sludges to generate biochar adsorbents or catalysts fosters a circular economy, curtailing sludge processing outlay. Biochars, carbonaceous substances synthesized via the thermochemical transformation of biomass, possess very high porosity, cation exchange capacity, specific surface area, and active functional sorption sites making them very effective as multifaceted adsorbents, promoting a negative carbon emission technology. By customizing the processing parameters and biomass feedstock, engineered biochars possess discrete physicochemical characteristics that engender greater efficaciousness for adsorbing various contaminants. This review provides explicit insight into the characteristics, environmental impact considerations, and SWOT analysis of different sludges (drinking water, fecal, and raw sewage sludge) and the contemporary biochar production, modification, characterization techniques, and physicochemical characteristics, factors influencing the properties of biochars derived from the aforestated sludges, along with the designing of chemical reactors involved in biochar production. This paper also manifests a state-of-the-art discussion of the utilization of sludge-derived biochars for the eviction of toxic metal ions, organic compounds, microplastics, toxic gases, vermicomposting approaches, and soil amelioration with an emphasis on biochar recyclability, reutilization, and toxicity. The practicability of scaling up biochar generation with multifaceted, application-accustomed functionalities should be explored to aggrandize socio-economic merits