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In this study, we utilized lime mud waste from paper mills to synthesize calcium hydroxide (Ca(OH)2) nanoparticles (NPs) and investigate their application for the removal of phosphorus from aqueous solution. The NPs, composed of green portlandite with hexagonal shape, were successfully produced using a precipitation method at moderately high temperature. The crystal structure and characterization of the prepared Ca(OH)2 nanoparticles were analyzed by field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. The effects of Ca(OH)2 NP dosage and contact time on removal of phosphorus were also investigated. The results show that the green portlandite NPs can effectively remove phosphorus from aqueous solution. The phosphorus removal efficiencies within 10 min are 53%, 72%, 78%, 98%, and 100% with the different mass ratios of Ca(OH)2 NPs/phosphorus (CNPs/P) of 2.2, 3.5, 4.4, 5.3, and 6.2, respectively. Due to the efficient phosphorus removal, the calcium hydroxide nanoparticles (CNPs) could be a potential candidate for this application in domestic or industrial wastewater treatment.

For decades, researchers have debated whether climate change has an adverse impact on diseases, especially infectious diseases. They have identified a strong relationship between climate variables and vector’s growth, mortality rate, reproduction, and spatiotemporal distribution. Epidemiological data further indicates the emergence and re-emergence of infectious diseases post every single extreme weather event. Based on studies conducted mostly between 1990-2018, three aspects that resemble the impact of climate change impact on diseases are: (a) emergence and re-emergence of vector-borne diseases, (b) impact of extreme weather events, and (c) social upliftment with education and adaptation. This review mainly examines and discusses the impact of climate change based on scientific evidences in published literature. Humans are highly vulnerable to diseases and other post-catastrophic effects of extreme events, as evidenced in literature. It is high time that human beings understand the adverse impacts of climate change and take proper and sustainable control measures. There is also the important requirement for allocation of effective technologies, maintenance of healthy lifestyles, and public education.

Excessive supply of phosphorus, a vital macronutrient for all organisms, can cause unwanted environmental consequences such as eutrophication. An increase in agricultural and industrial activities has created a considerable imbalance in the phosphorus cycle with continuing adverse effects on sustainability and ecosystem health, thereby stipulating/postulating the significance of phosphorus removal. A unique and sustainable concept for the removal of phosphorus through the utilization of waste bivalve seashells was proposed in the present study. Flat-surfaced and hexagonally shaped nanocalcium hydroxide particles (∼96% purity) with size ranging from 100 to 400 nm have been synthesized, and phosphorus from its aqueous solution is treated via precipitation. An optimization study has been conducted using the Box−Behnken design of response surface methodology, which highlights that with a calcium/phosphorus mass ratio, pH, and temperature of 2.16, 10.20, and 25.48 °C, a phosphorus removal efficiency of 99.33% can be achieved in a residence time of 10 min. Also, under the same conditions, diluted human urine was analyzed and phosphorus removal efficiency of ∼95% was observed. Through experimental results, semiquantitative phase analysis, and transmission electron microscopy, it has been found that the reaction was diffusion-controlled, which was further confirmed through shrinking core diffusion modeling. The present study manifests the promising potential of waste seashell-derived nanocalcium hydroxide for phosphorus treatment and its precipitation in the form of value-added hydroxyapatite.

In this study, we present a low-cost and simple method to treat spent lead–acid battery wastewater using quicklime and slaked lime. The sulfate and lead were successfully removed using the precipitation method. The structure of quicklime, slaked lime, and resultant residues were measured by X-ray diffraction. The obtained results show that the sulfate removal efficiencies were more than 97% for both quicklime and slaked lime and the lead removal efficiencies were 49% for quicklime and 53% for slaked lime in a non-carbonation process. After the carbonation step, the sulfate removal efficiencies were slightly decreased but the lead removal efficiencies were 68.4% for quicklime and 69.3% for slaked lime which were significantly increased compared with the non-carbonation process. This result suggested that quicklime, slaked lime, and carbon dioxide can be a potential candidate for the removal of sulfate and lead from industrial wastewater treatment.

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In present work, environmentally benign green aragonite crystals were synthesized from waste chicken eggshells and bivalve seashells through a simple and low-cost wet carbonation method. This method involves a constant stirring of calcium oxide slurry and magnesium chloride suspension in aqueous solution with constraint carbon dioxide injection at 80 °C. The physicochemical properties of the synthesized aragonite were further compared with the aragonite synthesized from commercial calcium oxide. The morphological analysis, such as acicular shape and optimum aspect ratio (~21), were confirmed by scanning electron microscopy. The average crystal size (10–30 µm) and specific surface area (2–18 m2 g−1) were determined by particle size and Brunauer–Emmett–Teller analysis, respectively. Moreover, a schematic crystal growth mechanism was proposed to demonstrate the genesis and progression of aragonite crystal. Green aragonite can bridge the void for numerous applications and holds the potential for the commercial-scale synthesis with eggshells and bivalve seashells as low-cost precursors.

Climate change is considered to be a potential cause of global warming, which leads to a continuous rise in the global atmospheric temperature. This rising temperature also alters precipitation conditions and patterns, thereby causing frequent occurrences of extreme calamity, particularly droughts and floods. Much evidence has been documented by the Intergovernmental Panel on Climate Change, illustrating fluctuations in precipitation patterns caused by global climate change. Recent studies have also highlighted the adverse impact of climate change on river flow, groundwater recovery, and flora and fauna. The theoretical political approach and scientific progress have generated ample opportunities to employ previously allusive methods against impacts caused by varying climatic parameters. In this study, the current state of India’s water environment policy is compared with that of South Korea. The “3Is”—ideas, institutions, and interests—which are considered pillars in the international field of political science, are used as variables. The concept of “ideas” highlights the degree of awareness regarding climate change while formulating water environment policy. Here, the awareness of India’s management regarding emerging water issues related to climate change are discussed and compared with that of South Korea. The concept of “institutions” illustrates the key differences in water environment policy under the umbrella of climate change between both countries within the associated national administrations. India’s administrations, such as the Ministry of Environment, Forests, and Climate Change; the Ministry of Water Resources, River Development, and Ganga Rejuvenation; the Ministry of Rural Development; and the Ministry of Housing and Urban Affairs, are used as a case study in this work. Finally, the concept of “interest” elaborates the prioritization of key issues in the respective water environment policies. Common interests and voids in the policies of both countries are also briefly discussed. A comparison of India’s water environment policies with that of South Korea is made to expose the gaps in India’s policies with respect to climate change, thereby seeking to identify a solution and the optimal direction for the future of the water environment policy of India.