The present work evaluated the capability of Arthrospira platensis complete biomass (ACDW) and the lipid-free biomass (LFB) to remove ammonium ions (NH4+) from aquaculture wastewater discharge. Under controlled conditions in flasks filled with 100 mL of distilled water (synthetic aqueous solution), a batch process ion-exchange was conducted by changing the main parameters including contact times (15, 30, 45, 60, 120, and 180 min), initial ammonium ion concentrations (10, 20, 30, 40, 50, and 100 mg·L−1), and initial pH levels (2, 4, 6, 8, and 10) at various dosages of ACDW and LFB as adsorbents (0.02, 0.04, 0.06, 0.08, and 0.1 g). After lab optimization, ammonia removal from real aquaculture wastewater was also examined. The removal of ammonium using ACDW and LFB in the synthetic aqueous solution (64.24% and 89.68%, respectively) was higher than that of the real aquaculture effluents (25.70% and 37.80%, respectively). The data of IR and Raman spectroscopy confirmed the existence of various functional groups in the biomass of ACDW and LFB. The adsorption equilibrium isotherms were estimated using Freundlich, Langmuir, and Halsey models, providing an initial description of the ammonia elimination capacity of A. platensis. The experimental kinetic study was suitably fit by a pseudo-second-order equation. On the other hand, as a result of the treatment of real aquaculture wastewater (RAW) using LFB and ACDW, the bacterial counts of the LFB, ACDW, ACDW-RAW, and RAW groups were high (higher than 300 CFU), while the LFB-RAW group showed lower than 100 CFU. The current study is the first work reporting the potential of ammonia-loaded microalgae biomass as a feed source for the rotifer (Brachionus plicatilis). In general, our findings concluded that B. plicatilis was sensitive to A. platensis biomass loaded with ammonia concentrations. Overall, the results in this work showed that the biomass of A. platensis is a promising candidate for removing ammonia from aquaculture wastewater.

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Carbon capture and use may provide motivation for the global problem of mitigating global warming from substantial industrial emitters. Captured CO2 may be transformed into a range of products such as methanol as renewable energy sources. Polymers, cement, and heterogeneous catalysts for varying chemical synthesis are examples of commercial goods. Because some of these components may be converted into power, CO2 is a feedstock and excellent energy transporter. By employing collected CO2 from the atmosphere as the primary hydrocarbon source, a carbon-neutral fuel may be created. The fuel is subsequently burned, and CO2 is released into the atmosphere like a byproduct of the combustion process. There is no net carbon dioxide emitted or withdrawn from the environment during this process, hence the name carbon-neutral fuel. In a world with net-zero CO2 emissions, the anthroposphere will have attained its carbon hold-up capacity in response to a particular global average temperature increase, such as 1.5 °C. As a result, each carbon atom removed from the subsurface (lithosphere) must be returned to it, or it will be expelled into the atmosphere. CO2 removal technologies, such as biofuels with carbon sequestration and direct air capture, will be required to lower the high CO2 concentration in the atmosphere if the Paris Agreement’s ambitious climate targets are to be realized. In a carbon-neutral scenario, CO2 consumption with renewable energy is expected to contribute to the displacement of fossil fuels. This article includes a conceptual study and an evaluation of fuel technology that enables a carbon-neutral chemical industry in a net-zero-CO2-emissions environment. These are based on the use of collected CO2 as a feedstock in novel chemical processes, along with “green” hydrogen, or on the use of biomass. It will also shed light on innovative methods of green transformation and getting sustainable, environmentally friendly energy.

In this study, both radiation shielding capability and optical properties of prepared SiO2-ZnO-Na2CO3-H3BO3-BaCO3 glass composite with different concentrations of barium carbonate (0–30 mol%) have been studied. Gamma attenuation properties, such as the mass attenuation coefficient (MAC), mean free path (MFP), and exposure build-up factor (EBF), are experimentally and theoretically investigated. The detected XRD patterns for the prepared glass composites confirm their amorphous nature. It is evident from the obtained data that all tested parameters, such as mass density, molar volume, refractive index, dielectric constant, refraction loss (%), and molar refraction, have been increased as BaCO3 mol% increased. At the same time, the results of the optical bandgap show a gradual decrease with increasing barium concentration. It was also found that the mass attenuation coefficients increased with BaCO3 concentration from 0.078 at zero mol% BaCO3 to 0.083 cm2/g at 30 mol%. Moreover, the half-value layer (HVL) and the exposure build-up factor (EBF) up to 40 mfp penetration depth were investigated in addition to the effective atomic number (Zeff) and the corresponding equivalent atomic number (Zeq) at the energy range of 0.015–15 MeV. The produced glass composite might be considered for many shielding applications based on the obtained results that require a transparent shielding material.

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