Topic Review
Laser-Induced Breakdown Spectroscopy in Elemental Analysis
Laser-induced breakdown spectroscopy (LIBS) has evolved considerably in recent years, particularly the application of portable devices for the elemental analysis of solids in the field. However, aqueous analysis using LIBS instruments, either in the laboratory or in the field, is rather rare, despite extensive research on the topic since 1984. To achieve this, researchers examined the literature published between 1984 and 2023, comparing various settings and parameters in a database. There are four different categories of LIBS instruments: laboratory-based, online, portable, and telescopic. Additionally, there are four main categories of sample preparation techniques: liquid bulk, liquid-to-solid conversion, liquid-to-aerosol conversion, and hydride generation. Various experimental setups are also in use, such as double-pulse. Moreover, different acquisition settings significantly influence the sensitivity and therefore the detection limits. Documentation of the different methods of sample preparation and experimental settings, along with their main advantages and disadvantages, can help new users make an informed choice for a particular desired application. In addition, the presentation of median detection limits per element in a periodic table of elements highlights possible research gaps and future research opportunities by showing which elements are rarely or not analysed and for which new approaches in sample preparation are required to lower the detection limits.
  • 161
  • 29 Jan 2024
Topic Review
Groundwater Depletion and Degradation in North China Plain
Groundwater is an important natural resource in the North China Plain (NCP) with high economic benefits and social significance. It fulfills 60% of drinking and 70% of irrigation water requirements. Groundwater becomes unsafe for human consumption due to pollution caused by inappropriate waste disposal, industrial discharges, and agricultural runoff.
  • 57
  • 24 Jan 2024
Topic Review
Sustainable Water Resources Management in Saudi Arabia
Saudi Arabia is one of the most water-scarce nations in the world, with a huge demand-supply gap, and the situation is expected to worsen due to climate change. Conventional surface water resources are limited, while nonrenewable groundwater sources are depleted. To build a more resilient and sustainable water sector, the production of non-conventional water resources, specifically desalinated seawater and treated domestic wastewater, has steadily increased in recent years. As the country lacks perennial water resources, such as rivers or water bodies, it relies mainly on nonrenewable groundwater and desalinated water to meet its daily requirements. Although the government is attempting to regulate the agricultural sector, water consumption in agriculture remains relatively high. It presents an environmental challenge due to its heavy reliance on non-renewable groundwater resources. The anticipated increase in temperature and highly uncertain changes in the rainfall patterns in Saudi Arabia could lead to greater uncertainty when attempting to develop effective water resource management plans.
  • 230
  • 22 Dec 2023
Topic Review
Micro-Irrigation Technologies in India and Africa
Water is an essential resource for the realization of the United Nations’ 2030 Sustainable Development Goals. The increasing global food insecurity, hunger, human population, and uneconomical extraction and use of non-renewable resources require, among other things, a substantial intensification of agricultural production. In this context, there has been a need to adopt irrigation technologies, especially in developing countries where agriculture and its allied sectors employ more than 50% of the total population but account for up to 90% of the total freshwater consumptive use. India and Africa are at the crux of this conundrum, where there is an urgent need to build resilience with the already excessively allotted water resources. Innovative and water-efficient irrigation technologies could be one of the windows of opportunity to overcome water scarcity and enhance food security in these regions. 
  • 184
  • 08 Dec 2023
Topic Review
Contaminant Removal in Different Constructed Wetland Types
Constructed wetlands (CWs) are artificially engineered treatment systems that utilize natural cycles or processes involving soils, wetland vegetation, and plant and soil-associated microbial assemblages to remediate contaminated water and improve its quality. CW treatment systems are typically categorized as free-water surface(FWSCWs), surface-flow constructed wetlands (SFCWs), subsurface-flow constructed wetlands (SSFCWs), and hybrid constructed wetlands (HCWs). Depending on the flow direction, Subsurface-flow CWs (SSFCWs) can be further classified into horizontal subsurface-flow (HSSF) and vertical subsurface-flow (VSSF) systems.
  • 101
  • 20 Nov 2023
Topic Review
Practical Application of Zeolites as Adsorbent
Zeolites are crystalline micro- and mesoporous materials widely used as catalysts and sorbents. Zeolites are commonly used in separation processes in, e.g., the petrochemical and pharmaceutical industries as they can be made fairly specific to the target molecules, and since the main mechanisms behind the separation process (molecular sieving, electrostatic interaction, and polarization) are always reversible, zeolites are believed (under ideal situations) to be able to undergo a virtually unlimited number of adsorption–desorption cycles. This is important from a cost-efficiency perspective too, as the high initial costs can be compensated by the longer life, assured by excellent stability and ease of regeneration.
  • 99
  • 17 Nov 2023
Topic Review
Degradation of Per- and Polyfluoroalkyl Substances
Per- and polyfluoroalkyl substances (PFASs) are an emerging group of persistent organic pollutants in aquatic environments with high levels of toxicity and bioaccumulation. The risks posed by PFASs to the environment and health have attracted increasing attention. To remove them from water, advanced oxidation processes (AOPs), with the merits of high efficiency and low cost, are mainly used. Photo/electrocatalytic heterogeneous AOPs, with the assistance of nanostructured catalysts and external energy in the form of light/electricity, have emerged as one of the most powerful techniques, overcoming the difficulty associated with defluorination and achieving the effective and complete degradation of PFASs in water. The structures of photo/electrocatalysts play a critical role in the production of reactive oxygen species, the electron transfer process, and the degradation pathway and its efficiency. 
  • 147
  • 13 Nov 2023
Topic Review
Factors Affecting N2O Emissions from Wastewater Treatment Plants
Wastewater treatment plants (WWTPs) generate significant amounts of greenhouse gases, including carbon dioxide, methane and nitrous oxide. Nitrous oxide (N2O) is an important greenhouse gas with a global warming potential (GWP) 273 times that of carbon dioxide (CO2), contributing to ozone layer depletion and climate change. Therefore, even small amounts of N2O emissions can significantly contribute to total greenhouse gases (GHG) emissions. Thus, it can be concluded that the minimization of N2O emissions and the identification of the factors controlling these emissions constitute a great challenge.
  • 94
  • 07 Nov 2023
Topic Review
River Chief Information-Sharing System Practice in China
Controling river water pollution is one of the complex ecoenvironmental challenges facing China’s development today. The river chief information-sharing system (RCISS) in China is an institutional innovation carried out by the government to promote collaborative water governance in the era of big data. In China, the RCISS is primarily practiced at the provincial level. A three-dimensional and intelligent information-management system would be established according to the work plan of the RCS.
  • 140
  • 27 Oct 2023
Topic Review
Virtual Water Trade
As a semi-arid/arid country located in the northwest of Africa, Morocco is facing serious water scarcity driven by the dual stresses of decreasing availability of water resources and increasing water demands. Virtual water trade could be an effective tool to alleviate water scarcity.
  • 255
  • 24 Oct 2023
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