Effective utilization of discarded reverse osmosis post-carbon for adsorption of dyes from wastewater.

In this study, the deployment of post Reverse Osmosis (RO)-carbon as a adsorbent for dye removal from water has been investigated. The post RO-carbon was thermally activated (RO900), and the material thus obtained exhibited high surface area viz. 753 m2/g. In the batch system, the efficient Methylene Blue (MB) and Methyl Orange (MO) removal was obtained by using 0.08 g and 0.13 g/50 mL adsorbent dosage respectively. Moreover, 420 min was the optimized equilibration time for both the dyes. The maximum adsorption capacities of RO900 for MB and MO dyes were 223.29 and 158.14 mg/g, respectively. The comparatively higher MB adsorption was attributed to the electrostatic attraction between adsorbent and MB. The thermodynamic findings revealed the process as spontaneous, endothermic, and accompanied by entropy increment. Additionally, simulated effluent was treated, and >99% dye removal efficiency was achieved. To mimic an industrial perspective, MB adsorption onto RO900 was also carried out in continuous mode. The initial dye concentration and effluent flow rate were among the process parameters that were optimized using the continuous mode of operation. Further, the experimental data of continuous mode was fitted with Clark, Yan, and Yoon-Nelson models. Py-GC/MS investigation revealed that dye-loaded adsorbents could be pyrolyzed to produce valuable chemicals. The cost and low toxicity associated benefits of discarded RO-carbon over other adsorbents reveal the significance of the present study.

Bio-oil and biochar from the pyrolytic conversion of biomass: A current and future perspective on the trade-off between economic, environmental, and technical indicators.

Over the years, the transformation of biomass into a plethora of renewable value-added products has been identified as a promising strategy to fulfil high energy demands, lower greenhouse gas emissions, and exploit under-utilized resources. Techno-economic analysis (TEA) and life-cycle assessment (LCA) are essential to scale up this process while lowering the conversion cost. In this study, trade-offs are made between economic, environmental, and technical indicators produced from these methodologies to better evaluate the commercialization potential of biomass pyrolysis. This research emphasizes the necessity of combining LCA and TEA variables to assess the performance of the early-stage technology and associated constraints. The important findings based on the LCA analysis imply that most of the studies reported in literature focussed on the global warming potentials (GWP) under environmental category by considering greenhouse gases (GHGs) as evaluation parameter, neglecting many other important environmental indices. In addition, the upstream and downstream processes play an important role in understanding the life cycle impacts of a biomass based biorefinery. Under upstream conditions, the use of a specific type of feedstock may influence the LCA conclusions and technical priority. Under downstream conditions, the product utilization as fuels in different energy backgrounds is crucial to the overall impact potentials of the pyrolysis systems. In view of the TEA analysis, investigations towards maximizing the yield of valuable co-products would play an important role in the commercialization of pyrolysis process. However, comprehensive research to compare the conventional, advanced, and emerging approaches of biomass pyrolysis from the economic perspective is currently not available in the literature.