Biochar and nano-ferric oxide synergistically alleviate cadmium toxicity of muskmelon

The synergistic potential of biochar and nanoparticles in phytoremediation and enhancing cadmium tolerance in plants

Cadmium (Cd) is classified as a heavy metal (HM) and is found into the environment through both natural processes and intensified anthropogenic activities such as industrial operations, mining, disposal of metal-laden waste like batteries, as well as sludge disposal, excessive fertilizer application, and Cd-related product usage. This rising Cd disposal into the environment carries substantial risks to the food chain and human well-being. Inadequate regulatory measures have led to Cd bio-accumulation in plants, which is increasing in an alarming rate and further jeopardizing higher trophic organisms, including humans. In response, an effective Cd decontamination strategy such as phytoremediation emerges as a potent solution, with innovations in nanotechnology like biochar (BC) and nanoparticles (NPs) further augmenting its effectiveness for Cd phytoremediation. BC, derived from biomass pyrolysis, and a variety of NPs, both natural and less toxic, actively engage in Cd removal during phytoremediation, mitigating plant toxicity and associated hazards. This review scrutinizes the application of BC and NPs in Cd phytoremediation, assessing their synergistic mechanism in influencing plant growth, genetic regulations, structural transformations, and phytohormone dynamics. Additionally, the review also underscores the adoption of this sustainable and environmentally friendly strategies for future research in employing BC-NP microaggregates to ameliorate Cd phytoremediation from soil, thereby curbing ecological damage due to Cd toxicity.

Nano-biochar as a potential amendment for metal(loid) remediation: Implications for soil quality improvement and stress alleviation

Metal(loid) contamination of agricultural soils has become an alarming issue due to its detrimental impacts on soil health and global agricultural production. Therefore, environmentally sustainable and cost-effective solutions are urgently required for soil remediation. Biochar, particularly nano-biochar, exhibits superior and high-performance capabilities in the remediation of metal(loid)-contaminated soil, owing to its unique structure and large surface area. Current researches on nano-biochar mainly focus on safety design and property improvement, with limited information available regarding the impact of nano-biochar on soil ecosystems and crop defense mechanisms in metal(loid)-contaminated soils. In this review, we systematically summarized recent progress in the application of nano-biochar for remediation of metal(loid)-contaminated soil, with a focus on possible factors influencing metal(loid) uptake and translocation in soil-crop systems. Additionally, we conducted the potential/related mechanisms by which nano-biochar can mitigate the toxic impacts of metal(loid) on crop production and security. Furthermore, the application of nano-biochar in field trials and existing challenges were also outlined. Future studies should integrate agricultural sustainability and ecosystem health targets into biochar design/selection. This review highlighted the potential of nano-biochar as a promising soil amendment for enhancing the remediation of metal(loid)-contaminated agricultural soils, thereby promoting the synthesis and development of highly efficient nano-biochar towards achieving environmental sustainability.

Biosorption Potential of Arachis hypogaea-Derived Biochar for Cd and Ni, as Evidenced through Kinetic, Isothermal, and Thermodynamics Modeling

Biochar derived from plant biomass has great potential for the decontamination of aqueous media. It is the need of the hour to test biochar derived from economical, easily available, and novel materials. In this regard, the present study provides insight into the sorption of two heavy metals, i.e., cadmium (Cd) and nickel (Ni), using native Arachis hypogaea and its biochar prepared through pyrolysis. The effect of different factors, including interaction time, initial concentration of adsorbate, and temperature, as well as sorbent dosage, was studied on the sorption of Cd and Ni through a batch experiment. Characterization of the native biowaste and prepared biochar for its surface morphology and functional group identification was executed using Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). Results revealed the presence of different functional groups such as -OH on the surface of the adsorbent, which plays an important role in metal attachment. SEM reveals the irregular surface morphology of the adsorbent, which makes it easy for metal attachment. Thermogravimetric analysis shows the stability of A. hypogaea biochar up to 380 °C as compared with native adsorbent. The adsorption efficacy of A. hypogaea was found to be higher than that of native A. hypogaea for both metals. The best adsorption of Cd (94.5%) on biochar was observed at a concentration of 40 ppm, an adsorbent dosage of 2 g, a contact time of 100 min, and a temperature of 50 °C. While the optimum conditions for adsorption of Ni on biochar (97.2% adsorption) were reported at a contact time of 100 min, adsorbent dosage of 2.5 g, initial concentration of 60 ppm, and temperature of 50 °C. Results revealed that biochar offers better adsorption of metal ions as compared with raw samples at low concentrations. Isothermal studies show the adsorption mechanism as physical adsorption, and the negative value of Gibb's free energy confirms the spontaneous nature of the adsorption reaction. An increase in entropy value favors the adsorption process. Results revealed that the sorbent was a decent alternative to eliminate metal ions from the solution instead of costly adsorbents.