Synthesis of Nanocube‐Shaped Cobalt Tin Hydroxides for the Preconcentration of Lead in Environmental Seawater Collected from Antarctic Region

Here, a simple/efficient analytical strategy based on dispersive solid phase extraction was developed using CoSn(OH) 6 nanocubes for lead ions from environmental water samples by FAAS (flame atomic absorption spectrometry). CoSn(OH) 6 was synthesized as an adsorbent using the co‐precipitation method and characterized. The characterization studies proved the cube‐shaped morphology and uniform size distribution. The optimal experimental conditions were found by optimization studies and, the limit of quantification (LOQ), limit of detection (LOD), linear dynamic range were recorded as 37.6 μg/L, 11.3 μg/L, and 40–600 μg/L, respectively. The enhancement factor of the presented method was calculated as 158.7‐folds compared to the LOD of the conventional FAAS system. Recovery experiments were performed to check the method's applicability/accuracy and the percent recovery results varied from 89.0 % to 112.9 %. According to these findings, the developed method was successfully applied for the quantitative determination of the target analyte in a seawater sample matrix.

Transient X‐Ray Absorption Near Edge Structure Spectroscopy Using Broadband Free‐Electron Laser Pulses

A new method for time‐resolved X‐ray absorption near edge structure (XANES) spectroscopy that enables faster data acquisition and requires smaller sample quantities for high‐quality data, thus allowing the analysis of more samples in a shorter time is introduced. The method uses large bandwidth free electron laser pulses to measure laser‐excited XANES spectra in transmission mode. A beam‐splitting grating configuration allows simultaneous measurements of the spectra of the incoming X‐ray Free Electron Laser (XFEL) pulses and transmission XANES, which is crucial for compensating the pulse‐dependent intensity and spectrum fluctuations due to the self‐amplified spontaneous emission operation. The implementation of this new methodology is applied on a liquid solution of ammonium iron(III) oxalate jet and is compared to previous results, showing great improvements in the speed of acquisition and spectral resolution, and the ability to measure a large 2‐D spectral‐time map quickly.

Optimizing Advanced High‐Strength Steel Joints via Regional Rapid Cooling in Resistance Spot Welding

During resistance spot welding (RSW), the thermal cycles that occur cause microstructural differentiations in the heat‐affected zones of martensitic steels, leading to internal stresses. In this context, a new and innovative methodology has been developed to minimize the adverse effects of heterogeneous hardness changes in the welding area on joint durability. This methodology utilizes a unique prototype setup based on the regional rapid cooling (RRC) process, which is integrated into the welding machine and operates in synchronization with the machine during the process. Through this setup, the aim is to effectively control the microstructure and hardness values in the welding area. This innovative approach presents potential improvements in the field of welding technology by aiming to optimize material performance during the welding process. According to microstructure results, the RRC process has narrowed the heat‐affected zone to 1.27 mm, increased the hardness values by 9.2%, showed a 3% increase in tensile‐shear strength, a 9% increase in cross‐tension strength, and based on fatigue strength results, no fractures occurred in all specimens subjected to a force of 0.3 kN.

Equilibrium, kinetic, and thermodynamic studies on the biosorption of lead by human metallothionein gene‐cloned bacteria as a novel biosorbent

Heavy metals are the main pollutants in water and are an important global problem that threatens human health and ecosystems. In recent years, there has been an increasing interest in the use of genetically modified bacteria as an eco‐friendly method to solve heavy metal pollution problems. The goal of this study was to generate genetically modified Escherichia coli expressing human metallothioneins (hMT2A and hMT3) and to determine their tolerance, bioaccumulation, and biosorption capacity to lead (Pb 2+ ). Recombinant MT2A and MT3 strains expressing MT were successfully generated. Minimum inhibition concentrations (MIC) of Pb for MT2A and MT3 were found to be 1750 and 2000 mg L −1 , respectively. Pb 2+ resistance and bioaccumulation capacity of MT3 were higher than MT2A. Therefore, only MT3 biosorbent was used in Pb 2+ biosorption, and its efficiency was examined by performing experiments in a batch system. Pb 2+ biosorption by MT3 was evaluated in terms of isotherms, kinetics, and thermodynamics. The results showed that Pb biosorption fits to the Langmuir isotherm model and the pseudo‐first‐order kinetic model, and the reaction is exothermic. The maximum Pb 2+ capacity of the biosorbent was 50 mg Pb 2+ g −1 . The potential of MT3 in Pb biosorption was characterized by Fourier‐transform infrared spectroscopy (FT‐IR), scanning electron microscopy (SEM), and scanning transmission electron microscopy (STEM) analyses. The desorption study showed that the sorbent had up to 74% recovery and could be effectively used four times. These findings imply that this biosorbent can be applied as a promising, precise, and effective means of removing Pb 2+ from contaminated waters. Practitioner Points In this study, the tolerance levels, bioaccumulation, and biosorption capacities of Pb in aqueous solutions were determined for the first time in recombinant MT2A and MT3 strains in which human MT2A and MT3 genes were cloned. The biosorbent of MT3, which was determined to be more effective in Pb bioaccumulation, was synthesized and used in Pb biosorption. The Pb biosorption mechanism of MT3 biosorbent was identified using isotherm modeling, kinetic modeling, and thermodynamic studies. The maximum Pb removal percentage capacity of the biosorbent was 90%, whereas the maximum biosorption capacity was up to 50 mg Pb 2+ g −1 . These results indicated that MT3 biosorbent has a higher Pb biosorption capacity than existing recombinant biosorbents. MT3 biosorbent can be used as a promising and effective biosorbent for removing Pb from wastewater.

Circularity Criteria and Indicators at the Building Component and System Level

Circular Materials—A Multiscale Approach to Circularity at a Building, Components and Materials Level

CE Management

Improved mechanical and fire-retardant properties of fiber-reinforced composites manufactured via modified resins and metallic thin films

Climatology of severe hail potential in Europe based on a convection-permitting simulation

Polypseudophakia: from “Piggyback” to supplementary sulcus-fixated IOLs