Conversion of carbon black recovered from waste tires into activated carbon via chemical/microwave methods for efficient removal of heavy metal ions from wastewater.

In this research study, recovered carbon black (rCB) was obtained via pyrolysis of waste tires. The obtained rCB was then converted into activated carbon species through both chemical treatment and microwave coupled with chemical treatment as a two-step activation process. The activated carbon obtained from chemical activation was denoted as C-AC, while that obtained from exposure to microwave followed by chemical activation was labeled as MC-AC. These two structures were consequently introduced as sorbents for the removal of cadmium ions from an aqueous solution. The structural characteristics of the introduced adsorbents were confirmed using various techniques, namely X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, and energy-dispersive X-ray (EDX) spectroscopy. Additionally, textual features of these adsorbents were acquired via both scanning electron microscopy (SEM) and N2 adsorption-desorption BET surface area analyses. These two structures were then introduced for Cd ion adsorption under different operating conditions. Particularly, the effect of pH, contact time, adsorbent dose, and metal ion concentration on the efficiency of adsorption was investigated. The 1maximum adsorption capacity was detected at a pH value of 5.0, a contact time of 30 min, a sorbent dose of 0.4 g L-1, and an initial metal concentration of 50 mg L-1 using MC-AC, which exhibited nearly double the sorption capacity detected for C-AC. Kinetic studies indicated that the process of Cd(ii) adsorption is perfectly described and fitted by the pseudo-second-order model. However, adsorption isotherms for the two adsorbents were found to match the Langmuir model, referring to the occurrence of uniform monolayer adsorption for the metal ions. Thermodynamic analysis demonstrated that the adsorption process was spontaneous and endothermic.

Towards understanding climate change: Impact of land use indices and drainage on land surface temperature for valley drainage and non-drainage areas.

The continuous increase of urbanization and industrialization brought various climatic changes, leading to global warming. The unavailability of meteorological data makes remotely sensed data important for understanding climate change. Therefore, the land surface temperature (LST) is critical in understanding global climate changes and related hydrological processes. The main objective of this work is to explore the dominant drivers of land use and hydrologic indices for LST in drainage and non-drainage areas. Specifically, the relationship between LST changes, land use, and hydrologic indices in Northeast Qena, Egypt, was investigated. The Landsat 5 and 8 imagery, Geographic Information System (GIS), and R-package were applied to identify the change detection during 2000-2021. The normalized difference between vegetation index (NDVI), bare soil index (BSI), normalized difference built-up, built-up index (BUI), modified normalized difference water index (MNDWI), and soil-adjusted vegetation index (SAVI) were employed. The non-drainage or mountain areas were found to be more susceptible to high LST values. The comprehensive analysis and assessment of the spatiotemporal changes of LST indicated that land use and hydrologic indices were driving factors for LST changes. Considerably, LST retrieved from the Landsat imaginary showed significant variation between the maximum LST during 2000 (44.82°C) and 2021 (50.74°C). However, NDBI has got less spread during the past (2000) with 10-13%. A high negative correlation was observed between the LST and NDVI, while the SAVI and LST positively correlated. The results of this study provide relevant information for environmental planning to local management authorities.

Cadmium and iron removal from phosphoric acid using commercial resins for purification purpose.

Three commercial resins bearing sulfonic, amino phosphonic, or phosphonic/sulfonic reactive groups have been tested for the removal of iron and cadmium from phosphoric acid solutions. The sorption properties are compared for different experimental conditions such as sorbent dosage (0.5-2.5 g L-1), phosphoric acid concentration (from bi-component solutions, 0.25-2 M), and metal concentrations (i.e., in the range 0.27-2.7 mmol Cd L-1 and 0.54 mmol Fe L-1) with a special attention paid to the impact of the type of reactive groups held on the resins. The sulfonic-based resin (MTC1600H) is more selective for Cd (against Fe), especially at high phosphoric acid concentration and low sorbent dosage, while MTS9500 (aminophosphonic resin) is more selective for Fe removal (regardless of acid concentration and sorbent dosage). Equilibrium is reached within 2-4 h. The resins can be ranked in terms of cumulative sorption capacities according the series: MTC1600H > MTS9570 > MTS 9500. Sulfuric acid (0.5-1 M) can be efficiently used for the desorption of both iron and cadmium for MTC1600H, while for MTS9570 (phosphonic/sulfonic resin) sulfuric acid correctly desorbs Cd (above 96% at 1 M concentration), contrary to Fe (less than 30%). The aminophosphonic resin shows much poorer efficiency in terms of desorption. The sulfonic resin (i.e., MTC1600H) shows much higher sorption capacity, better selectivity, comparable uptake kinetics (about 2 h equilibrium time), and better metal desorption ability (higher than 98% with 1 M acid concentration, regardless of the type of acid). This conclusion is confirmed by the comparison of removal properties in the treatment of different types of industrial phosphoric acid solutions (crude, and pre-treated H3PO4 solutions). The three resins are inefficient for the treatment of crude phosphoric acid, and activated charcoal pre-treatment (MTC1600H reduced cadmium content by 77%). However, MTC1600H allows removing over 93% of Fe and Cd for H3PO4 pre-treated by TBP solvent extraction, while the others show much lower efficiencies (< 53%).