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•Granulation followed by ferric loading had the best phosphate adsorption capacity.•The phosphate adsorption capacity was increased from 0 to 0.963mg/g.•Both granulation and ferric ...oxides loading obviously increased the surface areas.•Pseudo-first order model is allowable to estimate the adsorption kinetics.
Granulation of biochar powder followed by immobilization of ferric oxides on the macroporous granular biochar (Bg-FO-1) substantially enhanced phosphate removal from water. BET analysis confirmed that both granulation and ferric oxides loading can increase the surface areas and pore volumes effectively. Bg-FO-1 was proven to be a favorable adsorbent for phosphate. The phosphate adsorption capacity was substantially increased from 0mg/g of raw biochar powder to 0.963mg/g (Bg-FO-1). When the ferric oxides loading was prior to granulation, the adsorption capacity was decreased by 59–0.399mg/g, possibly due to the decrease of micropore and mesopore area as well as the overlaying of binders to the activated sites produced by ferric oxides.
Algae-bacteria consortia treatment has been found to be a promising method for the remediation of aqueous systems. Given the scope of previous reviews on algae-bacteria interactions, the sections on ...chemical signaling between algae and bacteria don't cover the current knowledge gap, and recent advances of algae-bacteria consortia in aqueous remediation don't explore the full depth. Accordingly, the specific aim of this review was to thoroughly screen and summarize recent peer-reviewed literature on (1) the mechanism of algal selection and enrichment in wastewater treatment; (2) interactions between algae and bacteria in ecological niche environments; (3) chemical signaling between algae and bacteria; (4) aqueous remediation using the algae-bacteria consortia; and (5) advanced treatment techniques combined with algae-bacteria systems for improved aqueous remediation. The main current challenges and future perspectives in algae-bacteria consortia wastewater treatment are proposed, including: (i) comprehensively establishing the network of interactions between algae and bacteria, especially quorum sensing and phycospheric interactions; (ii) developing a detailed understanding of the chemical exchange between microbial species based on molecular diffusion processes; (iii) tracking complex algae-bacteria interactions in aquatic environments using machine learning (ML), providing a potential tool for the design of beneficial and customizable synthetic microbial communities for wastewater treatment; (iv) integrating advanced treatment techniques (e.g., MBRs, UV photolysis and biological activated carbon) with algae-bacteria consortia systems, increasing the sustainability and applicability of treatment processes. Therefore, this review provides guidance and insights on the future development of algae-bacteria consortia treatment systems and their potential application for aqueous remediation.
•Macroalgae residue is promising raw material for producing biochar.•Biochar derived from pigments-extracted macroalgae is a promising adsorbent.•The malachite green adsorption capacity of MDBC800 is ...5306.2 mg/g.
Biochar is known to efficiently adsorb dyes from wastewater. In this study, biochar was derived from macroalgae residue by pyrolysis, and the influence of varying temperature (from 400 °C to 800 °C) on biochar characteristics was investigated. Among the biochar samples tested, macroalgae-derived biochar possessing highly porous structure, special surface chemical behavior and high thermal stability was found to be efficient in removing malachite green, crystal violet and Congo red. The biochar derived by pyrolysis at 800 °C showed the highest adsorption capacity for malachite green (5306.2 mg g−1). In this study, the transformation of microalgae residue into a highly efficient dye adsorbent is a promising procedure for economic and environmental protection.
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•AOPs are effective technologies for oxidative pathogen elimination.•The key mechanisms of AOPs-based disinfection are discussed.•The characteristics of ROS and their inactivation ...pathways are showcased.•ROS oxidatively damaged the cell membrane, enzymes, and genetic materials.•Operational cost and energy consumption of different AOPs are analyzed.
The disinfection of microbial pathogens plays an important role in control of waterborne diseases and health issues. Recently, advanced oxidation processes (AOPs) are applied as powerful and effective technologies for wastewater purification and pathogen elimination. This review will showcase the recent endeavors in the fields and provide a comprehensive understanding of pathogens inactivation by diverse AOPs (i.e., Fenton processes, photocatalysis, electrochemical advanced oxidation processes (EAOPs), sonolysis, ozonation, and persulfate-based AOPs). The mechanisms of AOPs-based disinfection include the destruction of cell envelope, enzymes, and intracellular substances via diverse reactive oxygen species (ROS). The primary ROS are HO·, SO4•−, O2•−, 1O2, and O3, which exhibit different oxidative capacities, and can react with cell envelope to destroy the permeability of cell membrane. Specifically, this review emphasizes on the performances and mechanisms of different AOPs systems in microbial inactivation as well as perspectives in practical applications of disinfection in terms of feasibility, operating cost, and sustainability.
•Four industrial wastewaters treated by microalgae-bacteria consortia were reviewed.•Photobioreactor design for wastewater treatment with microalgae were described.•Feasibility and potential of ...microalgae-based wastewater treatment was evaluated.
Although microalgae can serve as an appropriate alternative feedstock for biofuel production, the high microalgal cultivation cost has been a major obstacle for commercializing such attempts. One of the feasible solution for cost reduction is to couple microalgal biofuel production system with wastewater treatment, as microalgae are known to effectively eliminate a variety of nutrients/pollutants in wastewater, such as nitrogen/phosphate, organic carbons, VFAs, pharmaceutical compounds, textile dye compounds, and heavy metals. This review aims to critically discuss the feasibility of microalgae-based wastewater treatment, including the strategies for strain selection, the effect of wastewater types, photobioreactor design, economic feasibility assessment, and other key issues that influence the treatment performance. The potential of microalgae-bacteria consortium for treatment of industrial wastewaters is also discussed. This review provides useful information for developing an integrated wastewater treatment with microalgal biomass and biofuel production facilities and establishing efficient co-cultivation for microalgae and bacteria in such systems.
•Sludge components and dewatering methods impact the properties of biochar.•Thermochemical methods influence the characteristics of sludge biochar.•The mechanisms and removal performance of ...pollutants by biochar are introduced.•High-temperature carbonized sludge biochar exhibits excellent performance.•This review offers a sustainablewayof sludge reutilizationfor water purification.
Environment-friendly and cost-effective disposal and reutilization of sludge wastes are essential in wastewater treatment processes (WWTPs). Converting activated sludge into biochar via thermochemical treatment is a promising technology for waste management in WWTPs. This review summarizes the compositions of sludge, the dewatering methods, and the thermochemical methods whichinfluence the structures, chemistry, and catalytic performances of the derived biochar. Moreover, the physiochemical characteristics and chemical stability of sludge biochar are discussed. Catalytic applications of biochar are highlighted, including the reaction mechanisms and feasibility for catalytic removal of organic contaminants. High-temperature carbonized sludge biochar exhibits excellent performance for persulfate activation in advanced oxidation processes due to the graphitic carbon structure, newly-created active sites, and fine-tuned metal species. Therefore, the sludge biochar can be produced via cost-effective and eco-friendly approaches to immobilize harmful components from sludge and remediate organic pollution in wastewater, offering a sustainable route toward sludge reutilization into value-added products for water purification.
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•The state-of-art lignocellulose pretreatment was comprehensively reviewed.•The advances in bioenergy production from pretreated lignocellulose was described.•The review covers key ...challenges associated with the lignocellulose pretreatment.•New strategies for overcoming pretreatment barriers were highlighted.
As a clean and renewable energy, bioenergy is one of the most promising alternatives to fossil fuels. Lignocellulose possesses great potential for bioenergy production, but the recalcitrant and heterogeneous structure limits its application. Pretreatment technology offers an effective solution to fractionate the main components of the lignocellulose and uncover the available cellulose. The obtained feedstock can be applied to bioconversion into energy, e.g., bioethanol, biogas, biohydrogen, etc. Here, the current state of lignocellulose pretreatment technologies was comprehensively reviewed, the advances in bioenergy production from pretreated lignocellulose was described, with particular attention to key challenges involved. Several new strategies for overcoming pretreatment barriers to realize highly efficient lignocellulose bioconversion were highlighted. The insights given in this review will facilitate further development on lignocellulosic bioenergy production, towards addressing the global energy crisis and climate change related to the use of fossil fuels.
•Anaerobic digestion sludge (ADS) is promising material for producing biochar.•Biochar derived from ADS is a promising adsorbent for heavy metal removal.•ADSBC600 can effectively adsorb Pb2+ with a ...adsorption capacity of 51.20mg/g.•Possible Pb2+ adsorption mechanisms are revealed.
The properties of biochar derived from waste activated sludge and anaerobic digestion sludge under pyrolysis temperature varying from 400°C to 800°C were investigated. The heavy metals adsorption efficiency of the sludge-derived biochar was also examined. Among the biochar samples tested, ADSBC600 possessing highly porous structure, special surface chemical behaviors and high thermal stability was found to remove Pb2+ from aqueous solutions efficiently with an adsorption capacity of 51.20mg/g. The Pb2+ adsorption kinetics and isotherm for ADSBC600 can be described using the pseudo second-order model and Langmuir isotherm, respectively. Analysis of the characteristics of biochar before and after metal treatment suggests that electrostatic attraction, precipitation, surface complexation and ion exchange are the possible Pb2+ removal mechanisms. This study demonstrates a successful example of waste refinery by converting anaerobic digestion sludge to feasible heavy metal adsorbents to implement the concept of circular economy.
•The accumulation of VFAs was affected by temperature significantly.•Low temperature accelerated membrane fouling process.•Proteins were the dominant EPSs causing membrane fouling at low ...temperature.•Granular active carbon can mitigate membrane fouling via protein absorption.
The performance of a novel integrated anaerobic fluidized-bed membrane bioreactor (IAFMBR) for treating practical domestic wastewater was investigated at a step dropped temperature from 35, 25, to 15°C. The COD removal was 74.0±3.7%, 67.1±2.9% and 51.1±2.6% at 35, 25 and 15°C, respectively. The COD removal depended both on influent strength and operational temperature. The accumulation of VFAs (Volatile Fatty Acids) was affected by temperature, and acetic acid was the most sensitive one to the decrease of temperature. The methanogenic activity of the sludge decreased eventually and the methane yield was dropped from 0.17±0.03, 0.15±0.02 to 0.10±0.01L/Ld. And as compared with a mesophilic temperature, a low temperature can accelerate membrane biofouling. Proteins were the dominant matters causing membrane fouling at low temperature and membrane fouling can be mitigated by granular active carbon (GAC) through protein absorption.
Biochars are low-cost and environmental-friendly materials, which are promising in wastewater treatment. In this study, biochars were manufactured from C-phycocyanin extracted (C-CP) Spirulina ...residue (SDBC) via thermal pyrolysis. Simultaneously, N-doping was also achieved from the protein in the algae for obtaining a high-performance carbocatalyst for peroxydisulfate (PDS) activation. The SDBC yielded large specific surface areas, nitrogen loading, and good conductivity, which demonstrated excellent oxidation efficiencies toward a wide array of aqueous microcontaminants. An in-depth mechanistic study was performed by integrating selective radical scavenging, solvent exchange (H2O to D2O), diverse organic probes, and electrochemical measurement, unveiling that SDBC/PDS did not rely on free radicals or singlet oxygen but a nonradical pathway. PDS intimately was bonded with a biochar (SDBC 900-acid, pyrolysis at 900 °C) to form a surface reactive complex that subsequently attacked an organic sulfamethoxazole (SMX) adsorbed on the biochar via an electron-transfer regime. During this process, the SDBC 900-acid played versatile roles in PDS activation, organic accumulation and mediating the electron shuttle from SMX to PDS. This nonradical system can maintain a superior oxidation efficiency in complicated water matrix and long-term stable operation. More importantly, the nonradical species in SDBC 900-acid/PDS system were capable of inactivating the bacteria (Escherichia coli) in wastewater. Therefore, the biochar based nonradical system can provide a mild and high-efficiency strategy for disinfection in waste and drinking water by green carbocatalysis. This study provides not only a value-added biochar catalyst for wastewater purification but also the first insight into the bacteria inactivation via nonradical oxidation.
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•N-doped graphitic biochar (SDBC) was fabricated from Spirulina residue after C-phycocyanin extraction.•The protein in Spirulina residue works as natural nitrogen precursors.•The residual inorganic salts can function as pore forming agents.•SDBC were effective in persulfate activation for sulfamethoxazole degradation.•Carbon based nonradical oxidation can effectively inactivate bacteria in wastewater.
