A new insight into the restriction of Cr(VI) removal performance of activated carbon under neutral pH condition.

Water Sci Technol

Instituto de metalurgia, Universidad Autónoma de San Luis Potosí, Av. Sierra Leona 550 C.P. 78210, San Luis Potosí, Mexico.

Published: November 2021

Activated carbon has been widely used to remove hazardous Cr(VI); however, the impact of CrO precipitate on gradually declining removal ability as pH increases has received little attention. Herein, to investigate the effect of CrO, SEM-EDX (scanning electron microscope-energy dispersive X-ray analysis) coupling elements mapping of chromium-loaded powdered activated carbon (PAC) revealed that a chromium layer was formed on the PAC exterior after being treated with Cr(VI) at pH 7. XPS (X-ray photoelectron spectroscopy) study confirmed that 69.93% and 39.91% CrO precipitated on the PAC surface at pH 7 and pH 3, respectively, corresponding to 17.77 mg/g and 20 mg/g removal capacity. Exhausted PAC had a removal efficiency of 92.43% after CrO being washed by HSO solution, which was much higher than the removal efficiency of 51.27 % after NaOH washing. This further verified that the intrinsically developed CrO precipitate on PAC under neutral conditions limited the durability of PAC as an adsorbent. Consecutive elution assessments confirmed that adsorption and reduction ability both declined as pH increased. Raman spectroscopy and C 1s spectra of materials demonstrated two distinct Cr(VI) removal mechanisms under pH 3 and pH 7. In conclusion, the exhausted AC after Cr(VI) adsorption can be rejuvenated after the surface coated CrO is washed by the acid solution, which can expand the longevity of AC and recover Cr(III).

Download full-text PDF

Source
http://dx.doi.org/10.2166/wst.2021.449DOI Listing

Publication Analysis

Top Keywords

activated carbon
12
crvi removal
8
cro precipitate
8
removal efficiency
8
cro washed
8
removal
6
cro
6
pac
6
crvi
5
insight restriction
4

Similar Publications

Spontaneously Photocatalytic Nanoplatform for Sensitive Diagnosis and Penetrated Therapy of Cancer.

Anal Chem

January 2025

Collaborative Innovation Center of Tumor Marker Detection Technology, Equipment and Diagnosis-Therapy Integration in Universities of Shandong, Shandong Province Key Laboratory of Detection Technology for Tumor Makers, School of Chemistry and Chemical Engineering, Linyi University, Linyi 276005, China.

In this study, a sensitive diagnosis and spontaneously photocatalytic therapy of cancer based on chemiluminescence (CL) and nanozyme was studied. Briefly, carbon nitride-supported copper nanoparticles (CuCNs) loaded with luminol (CuCN-L) were utilized to develop a microneedle patch (CuCN-L/MN). The CuCN-L probe could target overexpressed HO in the TME and actively emit CL to achieve cancer cell imaging for diagnosis.

View Article and Find Full Text PDF

The study reports solid-state ceramic supercapacitors (SSCs) assembled using a novel composite electrolyte based on Li ion conducting perovskite-type LLTO (LiLaTiO) and an ionic liquid (EMIM BF). Small amounts of various ionic liquids (ILs) were added to LLTO to enhance the ionic conductivity and improve electrode compatibility. The optimal composition with approximately ∼6 wt% EMIM BF in LLTO exhibited a high ionic conductivity of around ∼10 Ω cm at room temperature, nearly three orders of magnitude higher than that of the pristine LLTO.

View Article and Find Full Text PDF

Cdc42 is crucial for the early regulation of hepatic stellate cell activation.

Am J Physiol Cell Physiol

January 2025

Department of Anatomy and Regenerative Biology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan.

The activation of hepatic stellate cells (HSCs) from a quiescent state is a cause of liver fibrosis and a therapeutic target. HSCs are resident mesenchymal cells located in the space of Disse, exhibiting specialized morphological characteristics such as a stellate shape, large lipid droplets, and direct adhesions to hepatocytes via microprojections called HSC spines. Morphological alterations in HSCs play a crucial role in initiating their activation.

View Article and Find Full Text PDF

Cobalt-Cluster-Based Metal-Organic-Framework-Catalyzed Carboxylative Cyclization of Propargylic Amines with CO from Flue Gas.

Inorg Chem

January 2025

Frontiers Science Center for New Organic Matter, Key Laboratory of Advanced Energy Materials Chemistry (MOE), College of Chemistry, Nankai University, Tianjin 300071, China.

The fixation of carbon dioxide (CO) directly from flue gas into valuable chemicals like 2-oxazolidinones is of great significance for economic and environmental benefits, which is typically catalyzed by noble-metal catalysts and under harsh conditions. Herein, a novel 2-fold interpenetrated framework {[Co(μ-O)(TCA)(HDPTA)]·2HO·2DMF} [Co(II)-based metal-organic framework ()] containing [Co] clusters and highly dense amino groups (-NH) dispersed in the channel was prepared, exhibiting high solvent/pH stability and CO adsorption capacity (24.9 cm·g).

View Article and Find Full Text PDF

The remediation of wastewaters contaminated with dyes (discharged mainly from industry) is very important for preserving environmental quality and human health. In this study, a new composite chitosan (CS)-based adsorbent combined with activated carbon (AC) and curcumin (Cur) (abbreviated hereafter as CS/AC@Cur) in three different ratios (12.5%, 25%, and 50%) was synthesized for the removal of anionic [reactive black 5 (RB5)] and cationic [methylene blue (MB)] dyes in single-component or binary systems.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!