Fabrication of microwave assisted biogenic magnetite-biochar nanocomposite: A green adsorbent from jackfruit peel for removal and recovery of nutrients in water sample

Biogenic, sustainable cellulose nanocrystals for removal of pharmaceuticals from water: a prospective upgradation and value addition of Grewia Optiva fiber

Biogenic, sustainable adsorbents in general and more specifically from cellulosic origin are in demand for enabling cost-effective and environmentally friendly wastewater treatment. A novel carbonaceous, highly crystalline, mesoporous cellulose-nanocrystal (GOF@n-CL) was extracted from Grewia Optiva fiber (GOF) via 40 % H2SO4 hydrolysis and successfully applied for adsorptive removal of some pharmaceuticals (Diclofenac, Ciprofloxacin, Tetracycline, Ofloxacin, Norflox-TZ) from wastewater. While 13C NMR and FTIR spectral data confirmed the sanctity of cellulosic structure, XRD revealed cellulose-I structure having high crystallinity of 77.4 % in the fabricated GOF@n-CL. TEM analysis revealed a networked porous structure due to agglomeration of nearly spherical shaped GOF@n-CL with SAED confirming its poly-crystalline nature. Batch studies showed 96 % tetracycline (TTC) removals by GOF@n-CL and isotherm studies reflected its binding affinity was onto the heterogeneous surface. Physisorption binding mechanism via the involvement of pore diffusion, hydrogen bonding and electrostatic interactions was indicated from kinetics and from FTIR studies. The efficacy of the GOF@n-CL was further demonstrated by high removals of ciprofloxacin (81 %), diclofenac (46 %), ofloxacin (78 %) (under single adsorbate system) and of norflox-TZ (norfloxacin-48 %; trinidazole-35 %; dual adsorbate system). The promising results have suggested a pathway for upgradation of GOF to value added water-based biogenic and sustainable adsorbents.

Phosphorus recovery and reuse: Innovating with biochar in the circular economy

Global challenges of phosphorus pollution and scarcity underscore an urgent need for the efficient recycling of this critical resource. Biochar, a sustainable and economical material, has demonstrated significant potential as an adsorbent for phosphorus, offering a viable solution for its recovery from wastewater. Various techniques have been explored to improve the ability of biochar to adsorb inorganic phosphate. While numerous studies have reviewed methods of biochar modification, the underlying adsorption mechanisms, and the thermodynamics and kinetics involved, a thorough examination that addresses the practical challenges of real-world wastewater treatment is currently lacking. This review aims to fill this gap by quantitatively analyzing the impact of coexisting species in wastewater on the adsorption of phosphate and by exploring the potential for simultaneous removal of other contaminants, such as nutrients, heavy metals, and dissolved organic matter. The review also discusses factors that affect the desorption of phosphate from biochar and presents practical applications for biochars post-adsorption. These applications include their use as slow-release phosphorus fertilizers, additives in concrete, and as novel adsorbents for the removal of heavy metals. This comprehensive analysis serves to synthesize current research on phosphate recovery by biochars and to propose practical uses for the adsorbed phosphorus, thereby guiding the development of biochar adsorption technology towards more effective and practical phosphorus management strategies.

Advancing sustainable wastewater management: A comprehensive review of nutrient recovery products and their applications

Wastewater serves as a vital resource for sustainable fertilizer production, particularly in the recovery of nitrogen (N) and phosphorus (P). This comprehensive study explores the recovery chain, from technology to final product reuse. Biomass growth is the most cost-effective method, valorizing up to 95 % of nutrients, although facing safety concerns. Various techniques enable the recovery of 100 % P and up to 99 % N, but challenges arise during the final product crystallization due to the high solubility of ammonium salts. Among these techniques, chemical precipitation and ammonia stripping/ absorption have achieved full commercialization, with estimated recovery costs of 6.0-10.0 EUR kgP-1 and 4.4-4.8 £ kgN-1, respectively. Multiple technologies integrating biomass thermo-chemical processing and P and/or N have also reached technology readiness level TRL = 9. However, due to maturing regulatory of waste-derived products, not all of their products are commercially available. The non-homogenous nature of wastewater introduces impurities into nutrient recovery products. While calcium and iron impurities may impact product bioavailability, some full-scale P recovery technologies deliver products containing this admixture. Recovered mineral nutrient forms have shown up to 60 % higher yield biomass growth compared to synthetic fertilizers. Life cycle assessment studies confirm the positive environmental outcomes of nutrient recycling from wastewater to agricultural applications. Integration of novel technologies may increase wastewater treatment costs by a few percent, but this can be offset through renewable energy utilization and the sale of recovered products. Moreover, simultaneous nutrient recovery and energy production via bio-electrochemical processes contributes to carbon neutrality achieving. Interdisciplinary cooperation is essential to offset both energy and chemicals inputs, increase their cos-efficiency and optimize technologies and understand the nutrient release patterns of wastewater-derived products on various crops. Addressing non-technological factors, such as legal and financial support, infrastructure redesign, and market-readiness, is crucial for successfully implementation and securing the global food production.