A Stable Fe-Zn Modified Sludge-Derived Biochar for Diuron Removal: Kinetics, Isotherms, Mechanism, and Practical Research

Artificial intelligence-enabled optimization of Fe/Zn@biochar photocatalyst for 2,6-dichlorophenol removal from petrochemical wastewater: A techno-economic perspective

While numerous studies have addressed the photocatalytic degradation of 2,6-dichlorophenol (2,6-DCP) in wastewater, an existing research gap pertains to operational factors' optimization by non-linear prediction models to ensure a cost-effective and sustainable process. Herein, we focus on optimizing the photocatalytic degradation of 2,6-DCP using artificial intelligence modeling, aiming at minimizing initial capital outlay and ongoing operational expenses. Hence, Fe/Zn@biochar, a novel material, was synthesized, characterized, and applied to harness the dual capabilities of 2,6-DCP adsorption and degradation. Fe/Zn@biochar exhibited an adsorption energy of -21.858 kJ/mol, effectively capturing the 2,6-DCP molecules. This catalyst accumulated photo-excited electrons, which, upon interaction with adsorbed oxygen and/or dissolved oxygen generated •O2-. The •OH radicals could also be produced from h+ in the Fe/Zn@biochar valence band, cleaving the C-Cl bonds to Cl- ions, dechlorinated byproducts, and phenols. An artificial neural network (ANN) model, with a 4-10-1 topology, "trainlm" training function, and feed-forward back-propagation algorithm, was developed to predict the 2,6-DCP removal efficiency. The ANN prediction accuracy was expressed as R2 = 0.967 and mean squared error = 5.56e-22. The ANN-based optimized condition depicted that over 90% of 2,6-DCP could be eliminated under C0 = 130 mg/L, pH = 2.74, and catalyst dosage = 168 mg/L within ∼4 h. This optimum condition corresponded to a total cost of $7.70/m3, which was cheaper than the price estimated from the unoptimized photocatalytic system by 16%. Hence, the proposed ANN could be employed to enhance the 2,6-DCP photocatalytic degradation process with reduced operational expenses, providing practical and cost-effective solutions for petrochemical wastewater treatment.

Removal of cadmium from aqueous solution by magnetic biochar: adsorption characteristics and mechanism

Experiments were conducted to investigate the potential of the efficient resource utilization of waste cow manure and corn straw in an agricultural ecosystem. In this study, a magnetic cow manure and straw biochar were synthesized by a co-precipitation method, and cadmium (Cd(II)) was removed by adsorption in aqueous solution. Several physicochemical characterization techniques were applied, including SEM, BET, Zeta, FTIR, Raman, XPS, and VSM. The effects of pH value, magnetic biochar content, adsorption kinetics, and isothermal adsorption on the adsorption of Cd(II) were investigated. The physicochemical characterizations revealed that the physical and chemical properties of the magnetic biochar were substantially changed compared to the unmodified biochar. The results showed that the surface of the biochar became rough, the number of oxygen (O)-containing functional groups increased, and the specific surface area increased. The results of the adsorption experiments showed that the adsorption capacity was affected by pH, magnetic biochar addition, Cd(II) concentration, and adsorption time. The adsorption kinetics and isothermal adsorption experiments showed that the Cd(II) adsorption processes of the cow manure and corn straw magnetic biochars were consistent with the Freundlich model and pseudo-second-order kinetic model. The results also showed that the Cd(II) adsorption effect of cow manure magnetic biochar was found to be more effective than that of corn straw magnetic biochar. The optimal conditions for Cd(II) adsorption were 800 ℃ for cow manure magnetic biochar, with a pH value of 5 and 0.14 g biochar addition, and 600 ℃ for straw magnetic biochar with a pH value of 8 and 0.12 g biochar addition. In conclusion, the cow manure magnetic biochar was an effective adsorbent for the absorption of Cd(II) in wastewater.

A review of novel methods for Diuron removal from aqueous environments

Runoff from intensive agriculture, which contains many sources of pollutants, including herbicides, for instance, Diuron, has threatened the environment and human health. The intrusion of these toxins into water sources poses a serious challenge to human society, and the rising release of these toxins has always been of concern to water researchers. The consequences of the release of these toxins into water sources are destructive and debilitating to human life. Today, the contamination of surface water and wastewater by pesticide residues, especially from agricultural activities and pesticide factories, has grown significantly. One of the pesticides commonly applied around the world is Diuron. There are various techniques for removing Diuron, the most important of which are adsorption and advanced oxidation. This review presents the characteristics, mechanisms, and emerging methods of removing Diuron. The use of absorbents, such as sludge-derived modified biochar (SDMBC600) and bottom ash waste (BAW-200), is discussed in detail. Additionally, the main features, benefits, and limitations of new technologies like hydrodynamic cavitation are enumerated. The effectiveness of novel adsorbents in Diuron removal is also discussed.

Efficient Adsorption of Tebuconazole in Aqueous Solution by Calcium Modified Water Hyacinth-Based Biochar: Adsorption Kinetics, Mechanism, and Feasibility

The application of fungicides (such as tebuconazole) can impose harmful impacts on the ecosystem and humans. In this study, a new calcium modified water hyacinth-based biochar (WHCBC) was prepared and its effectiveness for removing tebuconazole (TE) via adsorption from water was tested. The results showed that Ca was loaded chemically (CaC₂O₄) onto the surface of WHCBC. The adsorption capacity of the modified biochar increased by 2.5 times in comparison to that of the unmodified water hyacinth biochar. The enhanced adsorption was attributed to the improved chemical adsorption capacity of the biochar through calcium modification. The adsorption data were better fitted to the pseudo-second-order kinetics and the Langmuir isotherm model, indicating that the adsorption process was dominated by monolayer adsorption. It was found that liquid film diffusion was the main rate-limiting step in the adsorption process. The maximum adsorption capacity of WHCBC was 40.5 mg/g for TE. The results indicate that the absorption mechanisms involved surface complexation, hydrogen bonding, and π-π interactions. The inhibitory rate of Cu²⁺ and Ca²⁺ on the adsorption of TE by WHCBC were at 4.05-22.8%. In contrast, the presence of other coexisting cations (Cr⁶⁺, K⁺, Mg²⁺, Pb²⁺), as well as natural organic matter (humic acid), could promote the adsorption of TE by 4.45-20.9%. In addition, the regeneration rate of WHCBC was able to reach up to 83.3% after five regeneration cycles by desorption stirring with 0.2 mol/L HCl (t = 360 min). The results suggest that WHCBC has a potential in application for removing TE from water.