Enhanced copper (II) bioremediation from wastewater using nano magnetite (Fe3O4) modified biochar of Ascophyllum nodosum

Nano-enabled microalgae bioremediation: Advances in sustainable pollutant removal and value-addition

Microalgae-assisted bioremediation, enriched by nanomaterial integration, offers a sustainable approach to environmental pollution mitigation while harnessing microalgae's potential as a biocatalyst and biorefinery resource. This strategy explores the interaction between microalgae, nanomaterials, and bioremediation, advancing sustainability objectives. The potent combination of microalgae and nanomaterials highlights the biorefinery's promise in effective pollutant removal and valuable algal byproduct production. Various nanomaterials, including metallic nanoparticles and semiconductor quantum dots, are reviewed for their roles in inorganic and organic pollutant removal and enhancement of microalgae growth. Limited studies have been conducted to establish nanomaterial's (CeO2, ZnO, Fe3O4, Al2O3, etc.) role on microalgae in pollution remediation; most studies cover inorganic pollutants (heavy metals and nutrients) remediation, exhibited 50-300% bioremediation efficiency improvement; however, some studies cover antibiotics and toxic dyes removal efficiency with 19-95% improvement. These aspects unveil the complex mechanisms underlying nanomaterial-pollutant-microalgae interactions, focusing on adsorption, photocatalysis, and quantum dot properties. Strategies to enhance bioremediation efficiency are discussed, including pollutant uptake improvement, real-time control, tailored nanomaterial design, and nutrient recovery. The review assesses recent advancements, navigates challenges, and envisions a sustainable future for bioremediation, underlining the transformative capacity of nanomaterial-driven microalgae-assisted bioremediation. This work aligns with Sustainable Development Goals 6 (Clean Water and Sanitation) and 12 (Responsible Consumption and Production) by exploring nanomaterial-enhanced microalgae bioremediation for sustainable pollution management and resource utilization.

New insights into the remediation of chromium-contaminated industrial electroplating wastewater by an innovative nano-modified biochar derived from spent mushroom substrate: Mechanisms, batch study, stability and application

To enhance the adsorption and detoxification capabilities of hexavalent chromium (Cr(VI)) using agricultural spent mushroom substrate (SMS), this study pioneered the preparation of biochar (NBC) from Lentinus edodes spent substrate. Subsequently, nano iron sulfide (FeS) particles were integrated onto NBC with carboxymethyl cellulose (CMC) as a stabilizer, resulting in a novel composite biosorption material, nFeS-BC. The adsorption and reduction potential of both NBC and nFeS-BC against Cr(VI) were evaluated through batch experiments, which identified pH as a critical factor influencing adsorption efficiency. Remarkably, nFeS-BC exhibited a superior maximum adsorption capacity (qmax) of 99.57 mg g-1 and a reduction efficiency of 68.65%, outperforming NBC by 277.73% and 211.76% under optimized conditions, respectively. Characterization techniques including Scanning Electron Microscopy-Energy Dispersive X-Ray (SEM-EDX), Fourier Transform Infrared Spectroscopy (FT-IR), and X-ray Photoelectron Spectroscopy (XPS) elucidated the removal mechanisms, predominantly attributed to ion exchange, electrostatic attraction, functional group interaction, and redox reaction. The carbon-oxygen functional groups and nano particles were crucial in the adsorption and reduction processes. Compared with NBC, the incorporation of FeS particles increased the specific surface area and pore volume of nFeS-BC by 130.86% and 183.77%, respectively. nFeS-BC owned a shelf-life of up to ∼3 months of use and exhibited excellent performance in the processing of actual electroplating wastewater with q of 16.71 mg g-1 under 0.1 g L-1 dosage. These findings underscore the potential of nFeS-BC as an efficient material for Cr(VI) removal, presenting a novel adsorbent for the sustainable detoxification of contaminated water resources and the potential for using agricultural waste materials in environmental remediation.

Biosorption of cobalt and chromium from wastewater using manganese dioxide and iron oxide nanoparticles loaded on cellulose-based biochar: Modeling and optimization with machine learning (artificial neural network)

In this study, two nanomaterials with excellent adsorption capacities were developed to remove heavy metals efficiently from wastewater. Manganese dioxide MnO2 nanoparticles and iron oxide Fe2O3 nanoparticles were successfully synthesized using cassava peel carbon and characterized by different techniques. The experimental tests for the adsorption process were done in a batch system, and the influence of various parameters such as temperature (from 5 to 60 °C), initial concentration (from 10 to 60 mg/L), pH (2 to 8), and contact time (5 to 180 min) on the biosorption of cobalt (II) and chromium (VI) were fully investigated. Furthermore, the Qmax were 546.32 mg/g and 349.59 mg/g for chromium (VI) and cobalt (II) respectively. The results fitted Langmuir with the pseudo-second-order model, revealing that chemisorption controls heavy metals removal, while the thermodynamic sorption was an endothermic and spontaneous reaction. Artificial Neural Network (ANN) model was developed to predict as well as to simulate the experimental results, for this purpose, the proposed model was based on five independent inputs or variables and one output or response which is the predicted adsorbed amount, the proposed ANN model showed an appreciable prediction accuracy with high optimization ability for chromium (VI) and cobalt (II) removal.

Research advances on production and application of algal biochar in environmental remediation

Algae, comprising microalgae and macroalgae, have emerged as a promising feedstock for the production of functional biochar. Recently, the application of algal biochar in environmental remediation gains increasing attention. This review summarizes research advancements in the synthesis and application of algal biochar, a versatile and sustainable material for environmental remediation ranging from wastewater treatment to soil improvement. Algal biochar can be prepared by pyrolysis, microwave-assisted pyrolysis, and hydrothermal carbonization. Physical and chemical modifications have proven to be effective for improving biochar properties. Algal biochar is promising for removing diverse pollutants including heavy metals, organic pollutants, and microplastics. The role in soil improvement signifies a sustainable approach to enhancing soil structure, nutrient retention, and microbial activity. Research gaps are identified based on current understanding, necessitating further exploration into variations in biochar characteristics, the performance improvement, large-scale applications, and the long-term evaluation for environmental application. This review provides a better understanding of algal biochar as a sustainable and effective tool in environmental remediation.

Camel Dung-Derived Biochar for the Removal of Copper(II) and Chromium(III) Ions from Aqueous Solutions: Adsorption and Kinetics Studies

This study explores an innovative approach to tackle the critical issue of heavy metal ion contamination in aqueous solutions through the utilization of camel dung-derived biochar. In the context of global environmental concerns and the adverse impacts of heavy metal pollution on ecosystems and human health, the investigation focuses on copper(II) and chromium(III) ions, which are among the most pervasive pollutants originating from industrial activities. The research revealed that camel dung-derived biochar exhibits exceptional potential for the removal of copper(II) and chromium(III) ions, with removal efficiencies of more than 90% and adsorption capacities of 23.20 and 23.36 mg/g, respectively. The adsorption processes followed second-order kinetics, and the data fitted both the Langmuir and Freundlich adsorption models. The underlying mechanisms governing this adsorption phenomenon seem to be grounded in complexation reactions, cation exchange, and cation-π interactions, underscoring the multifaceted nature of the interactions between the biochar and heavy metal ions. This research not only advances our understanding of sustainable materials for water purification but also harnesses the underutilized potential of camel dung as a valuable resource for environmental remediation, offering a promising avenue for addressing global water pollution challenges.

Removal of typical pollutant ciprofloxacin using iron-nitrogen co-doped modified corncob in the presence of hydrogen peroxide

Iron-nitrogen co-doped modified corncob (Fe-N-BC) was synthesized using a hydrothermal and calcination method. The material shows excellent oxidation performance and environmental friendliness. When the dosage of Fe-N-BC was 0.6 g L-1, the concentration of H2O2 was 12 mM and pH was 4, ciprofloxacin (CIP) was virtually totally eliminated in 240 min under Fe-N-BC/H2O2 conditions. The TOC removal efficiency was 54.6%, and the effects of various reaction parameters on the catalytic activity of Fe-N-BC were thoroughly assessed. Through electron paramagnetic resonance (EPR) analyses and free radical quenching experiments, it was established that the reactive oxygen species (˙OH, ˙O2-, 1O2) were crucial in the elimination of CIP. Furthermore, the degradation of CIP was accelerated by the synergistic interaction between the transition metal and PFRs. A thorough evaluation was conducted to assess the respective contributions of adsorption and catalytic oxidation in the system. The degradation mechanism of CIP was proposed under Fe-N-BC/H2O2 conditions. Meanwhile, the possible degradation intermediates and pathways were proposed, and the toxicity of the degradation products of CIP was also meticulously investigated in the study. These findings offered the elimination of CIP in water a theoretical foundation and technical support.