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Mineral carbonation in aqueous solutions presents a pragmatic avenue for tackling the challenges associated with carbon capture, utilisation, and storage, particularly in limiting global temperature rise to 1.5 °C for climate change mitigation. The urgency to engineer the removal of atmospheric CO2 has driven the exploration of innovative methods for direct conversion into valuable products, with a specific emphasis on calcite as a promising approach for carbon dioxide sequestration. This investigation focuses on the biomimetic strategy of emulating the catalytic activity of carbonic anhydrase by synthesizing a zinc-based metal-organic framework. The MOF, synthesized with Zinc as the central metal coordinated by 1,2,3-benzene tricarboxylic acid, displays noteworthy structural adaptability, diversity, and an extensive surface area. The characterisation of synthesised materials through UV DRS, XRD, XPS, FTIR, SEM, and Raman analyses corroborates its structural features. A comparative study with a Nickel-based MOF (Ni-BTC-MOF) underscores the advantages of zinc over nickel in CO2 mineralisation experiments. Remarkably, Zn-BTC-MOF demonstrates superior catalytic activity, reusability, solvent compatibility, and thermal stability compared to Ni-BTC-MOF. The Zn-BTC-MOF catalyst achieves a mineralisation yield of 25 mg, comparable with the reported results for natural carbonic anhydrase (34.92 mg) and imidazole-carbonic anhydrase (21.55 mg). The Zn-BTC-MOF catalyst displays exceptional reusability, maintaining CO2 mineralisation activity across over a broad pH and temperature range. These findings underscore the potential of Zn-BTC-MOF as an effective biomimetic catalyst for carbon dioxide mineralisation, holding promising applications in carbon capture and utilization technologies. [ABSTRACT FROM AUTHOR]

In the present investigation, we report the formation of a metal–metal oxide (Zn/ZnO) nanoscale heterointerfac with concomitant hydrogen generation. The synthesis process is simple and involves the optical illumination of Zn nanoparticles (Zn(NP)) suspended in water. The concomitant hydrogen (H2) evolution during synthesis was found to be linear, and it is dependent on the growth of the Zn/ZnO nano interface. The progressively increasing amount of ZnO relative to Zn(NP) was a limiting factor in H2 evolution. Two different Zn/ZnO nanoscale heterointerfaces were created and samples were extracted at two different stages of the illumination process. The first sample, extracted from the most reactive illumination phase and named Zn(NP)/ZnO-R, had the highest hydrogen evolution reaction (HER) rate. The second sample, extracted from a less reactive illumination phase and named Zn(NP)/ZnO-S, had a lower HER rate. These in situ (solar light-induced) samples were characterized by XRD, HRTEM, and other methods. The optoelectronic features and the photoelectrochemical (PEC) investigations showed the optimal light-harvesting ability of Zn(NP)/ZnO-R and the effective separation of photoexcited charge carriers, leading to remarkable HER performance. During the visible-light-induced (in situ) conversion of Zn(NP) to Zn(NP)/ZnO-R, a concurrent HER rate of 1115 μmol h−1 was observed. Indeed, the photocurrent density value of the Zn(NP)/ZnO-R catalyst is significantly higher than that of Zn(NP)/ZnO-S, pristine Zn(NP), and ZnO. Thus, this study provides new insights into the optimal fabrication of the Zn(NP)/ZnO interface for PEC application with concomitant solar hydrogen generation. [ABSTRACT FROM AUTHOR]

In many developing and developed countries, presence of arsenite [As(III)] more than 10 ppb in groundwater is reported. Many people use the arsenic contaminated groundwater for drinking purposes, which is hazardous to human health. Hence need to be removed below the permissible level before use for drinking purpose. In this batch study, IBOA was used as an adsorbent to remove As(III) from water. From experimental data, optimal values for the dose of IBOA, time of contact and pH were found to be 1.0g/L, 24 hrs and 7.0, respectively. In this paper, ANN was applied to the various parameters and found that the results are satisfied in time study. Best fitting was found in dose study and initial concentration study where as in pH study, the ANN results and experimental results are in good agreement. In effect of coexisting ions study, ANN could not map in all cases and not shown the satisfactory results. From experimental data, it is proved that IBOA having good potential for removal of As(III) from groundwater. [ABSTRACT FROM AUTHOR]

Byline: Sadhana S. Rayalu, Nitin K. Labhsetwar Efforts are being made to develop nanomaterials for addressing issues related to energy, environment and resource conservation. In this connection, research is being conducted at Environmental Materials Unit in the area of development of nanosized structural analogues related to molecular sieves and zeolites, surface functionalised zeolites, pervoskite based catalytic materials, multifunctional metals/metal oxide materials, carbon and photocatalytically active materials. Several environmental and energy technologies have emerged with substantial benefits from nanotechnology, which include reduction in waste and improved energy efficiency, environmentally benign composite structures, waste remediation and energy conversion. Some of the key research areas include carbon capture, water-splitting reaction for hydrogen generation, biomimetic sequestration of CO2, and Diesel Particulate Filter (DPF) regeneration.