Life cycle sustainability assessment of crops in India

In India, the modernization in the agricultural sector is continuously growing to meet the food demand of rising population. However, along with addressing hunger, modern agriculture impacts the ecosystem, human health, and resources, due to huge consumption of agrochemicals, and emission-intensive farming hence urges sustainable assessment. Till now, no impact assessment is reported on world's second-largest agricultural country- India. This paper is the first of its kind in evaluating the impact of the cultivation of 21 commonly grown crops that possess high production and emissions in India. The results were discussed in the order of impact parameters in respective years with possible causes and remedial measures. The results showed that rice has topped in maximum indices followed by sugarcane, wheat, and banana. The study forecasted that coconut played a concentrated role in global warming, while potato and sugarcane have a higher impact on water and ozone depletion, respectively. The outcomes of this study suggested appropriate improvements in farming practices, which can bring the emissions down and make the system more sustainable. Besides, these 18 indices were individually assessed for their connection with the 17 sustainable development goals (SDGs) in the aspects of agricultural activities to select the appropriate indices to measure the agricultural sustainability along with the identification of gaps to upgrade the existing indices or formulate a new one. Subsequently, this helps in achieving the SDGs in India with the least impact on the environment without compromising the socio-economic aspects involved in crop production and agricultural systems. © 2021 The Author

Eco-safe chemicothermal conversion of industrial graphite waste to exfoliated graphene and evaluation as engineered adsorbent to remove toxic textile dyes

Industrial graphite becomes waste after its use and dumping of such graphite waste leads to environmental damage and health risks, thus needs alternative measures. This study is the first of its kind to convert industrial graphite to exfoliated graphene(EG) and using EG as an adsorbent. The used conversion method is chemicothermal which is greener and competent. The resultant EG was micro-analyzed for its application as an engineered adsorbent. The adsorption capacity of EG is tested for the removal of five toxic dyes from aqueous solution, namely royal blue (RB), turquoise blue (TB), black supra (BS), navy blue (NB), and deep red (DR) for various environmental conditions. The order of adsorption at equilibrium was found to follow, DR > TB > BS > NB > RB at circum-neutral pH in the range of 5 - 25 mg/L of dye, having 0.2 gm of EG. The notable adsorption capacity of dye onto EG can be credited to the various interface mechanisms which were studied using kinetic and thermodynamic models. The reusability studies recommend EG as the alternate adsorbent against commercial activated carbon which holds a huge carbon and water footprint. These results suggest that the applicability of potential EG adsorbent can be extended to the removal of organic pollutants in water and wastewater treatment. The success of converting graphite waste to an engineered dye adsorbent couples the advantages of converting industrial waste to a beneficial product and removal of toxic dyes thus achieving the circular economy and sustainable development in industrial practices

Graphene composites in photocatalytic oxidation of aqueous organic contaminants – A state of art

Graphene is a single layer of graphite and highly promising allotrope of carbon that attracted significant research interest because of its unique structure and physicochemical properties. Graphene derivatives exhibit exceptional crystal and electronic properties and have already emerged as a photocatalytic material due to its higher surface area, charge transfer and adsorption capability. Graphene composites made up of graphene derivatives with conventional photocatalysts enhanced the performance of photocatalysis by extending the light absorption ability, photostability, pollutant adsorption, catalysis etc. and makes it a suitable material for water and wastewater treatment. In this review, the fundamental characteristics of graphene composites for photocatalytic enhancement, different preparation methods, its application in the treatment of recalcitrant organic compounds under UV and visible spectrum and the speculated mechanisms are discussed. A critical review on the reuse potential of graphene composites and its importance in practical application of photocatalysis are first of its kind. At every segment, the summary of significances, existing gaps, pathways and challenges and pathways to proceed forward are added. The current review helps in the cohesive understanding of the state of art in the research field of graphene-based photocatalysis. © 2020 Institution of Chemical Engineer

Single-step removal of Hexavalent chromium and phenol using meso zerovalent iron

Novel meso-zero valent iron (mZVI) was investigated for treating complex wastewater containing toxic heavy metal Cr6+ and organic compound phenol. This study is first of its kind illustrating coupled removal in single-step with H2O2 playing a major role as an oxidant and reductant. The mechanism involved was electron transfer from Fe0/2+ to Cr6+ resulting in Fe2+/3+ which in turn was consumed for phenol oxidation returning as Fe2+ into the system for further Cr6+ reduction. While comparing, single-step simultaneous removal of Cr6+ and phenol showed better performance in terms of pollutant removal, Fe2+/3+ recurrent reaction and precipitation generation, double-tep sequential removal performed better in iron active-corrosion time. It was also observed that the entire redox cycle of Cr6+-Cr3+-Cr6+ was reusable for co-contaminant phenol degradation at all pH with the recurrence of Fe2+-Fe3+-Fe2+. The proposed technique was checked for its viability in a single batch reactor and the complex chemistry of the reactions are unfolded by conducting chemical speciation and mass balance study at every stage of reaction. The unique functioning of mZVI was proven with micro-analysis of ZVI's surface and compared with granular ZVI, cZVI. The results obtained from this study open the door for a safer and cleaner single treatment system in removing both toxic heavy metals and organic compounds from contaminated surface water, groundwater and many such industrial effluents