Sustainable methanol production from carbon dioxide: advances, challenges, and future prospects.

The urgent need to address global carbon emissions and promote sustainable energy solutions has led to a growing interest in carbon dioxide (CO2) conversion technologies. Among these, the transformation of CO2 into methanol (MeOH) has gained prominence as an effective mitigation strategy. This review paper provides a comprehensive exploration of recent advances and applications in the direct utilization of CO2 for the synthesis of MeOH, encompassing various aspects from catalysts to market analysis, environmental impact, and future prospects. We begin by introducing the current state of CO2 mitigation strategies, highlighting the significance of carbon recycling through MeOH production. The paper delves into the chemistry and technology behind the conversion of CO2 into MeOH, encompassing key themes such as feedstock selection, material and energy supply, and the various conversion processes, including chemical, electrochemical, photochemical, and photoelectrochemical pathways. An in-depth analysis of heterogeneous and homogeneous catalysts for MeOH synthesis is provided, shedding light on the advantages and drawbacks of each. Furthermore, we explore diverse routes for CO2 hydrogenation into MeOH, emphasizing the technological advances and production processes associated with this sustainable transformation. As MeOH holds a pivotal role in a wide range of chemical applications and emerges as a promising transportation fuel, the paper explores its various chemical uses, transportation, storage, and distribution, as well as the evolving MeOH market. The environmental and energy implications of CO2 conversion to MeOH are discussed, including a thermodynamic analysis of the process and cost and energy evaluations for large-scale catalytic hydrogenation.

Photocatalytic dye degradation using nickel ferrite spinel and its nanocomposite.

Coloured wastewater is a major issue of today for human health and ecology. Among all available processes such as physical, chemical, biological and electrochemical methods, photocatalysis can be a promising solution because of its ability to degrade colour-causing compounds completely by converting them into simpler molecules (H2O, CO2) depending on dye structure. In this work, NiFe2O4 was synthesized by the co-precipitation method. Furthermore, the composites of NiFe2O4 with TiO2 were synthesized by varying amounts of TiO2. The spinel and composites were characterized by XRD, ZETA analysis and UV-DRS. Their photocatalytic activities were investigated using the photocatalytic degradation of reactive turquoise blue 21 (RB 21) dye as model pollutants under sunlight. The increased absorption of the visible light and the enhanced separation of the electron-hole pairs due to the relative energy band positions in NiFe2O4 and TiO2 are considered as the main advantages. Our results showed that NiFe2O4-based nanocomposites could be used as an effective and magnetic retrievable photocatalyst.

Recent advances in developing innovative sorbents for phosphorus removal-perspective and opportunities.

Phosphorus is an essential mineral for the growth of plants which is supplied in the form of fertilizers. Phosphorus remains an inseparable part of developing agrarian economics. Phosphorus enters waterways through three different sources: domestic, agricultural, and industrial sources. Rainfall is the main cause for washing away a large amount of phosphates from farm soils into nearby waterways. The surplus of phosphorus in the water sources cause eutrophication and degradation of the habitat with an adverse effect on aquatic life and plants. Phosphate elimination is necessary to control eutrophication in water sources. Among the different methods reported for the removal and recovery of phosphorus: ion exchange, precipitation, crystallization, and others, adsorption standout as a sustainable solution. The current review offers a comparative assessment of the literature on novel materials and techniques for the removal of phosphorus. Herein, different adsorbents, their behaviors, mechanisms, and capacity of materials are discussed in detail. The adsorbents are categorized under different heads: iron-based, silica-alumina-based, calcium-based, biochar-based wherein the metal and metal oxides are employed in phosphorus removal. The ideal attribute of adsorbent will be the utilization of spent adsorbents as a phosphate plant food and a soil conditioner in agriculture. The review provides the perspective on the current research with potential challenges and directives for possible research in the field.

CO2 reduction routes to value-added oxygenates: a review.

Energy is a key attribute that is used to evaluate the economic development of any country. The demand for energy is going to rise in developing countries and will be 67% of global use by 2040. The energy surge in these rising economies will be responsible for 60-70% of the global greenhouse gas emissions. The quest for higher energy motivates technological development to curb the climate change occurring with GHG emissions. Carbon dioxide is one of the primary greenhouse gases in the atmosphere. Current work is intended to give an updated review on the different routes of carbon dioxide utilization that are catalytic route, photocatalytic route, electrocatalytic route, microwave plasma route, and biocatalytic route. These routes are capable of converting CO2 into different valuable products such as formic acid, methanol, and di-methyl ether (DME), which are majorly derived from biomass and/or fossil fuels (coal gasification and/or natural gas). This work investigates the effect of different routes available for the production of value-added products by CO2 reduction, discusses various challenges that come across the aforementioned routes, and shares views on future scope and research direction to pave new innovative ways of reducing CO2 from the environment.