Yam Code
Sign up
Login
New paste
Home
Trending
Archive
English
English
Tiếng Việt
भारत
Sign up
Login
New Paste
Browse
The Paraiba do Sul (PSR) and Guandu Rivers (GR) water diversion system (120 km long) is located in the main industrial pole of Brazil and supplies drinking water for 9.4 million people in the metropolitan region of Rio de Janeiro. This study aims to discern the trace metals dynamics in this complex aquatic system. We used a combined approach of geochemical tools such as geochemical partitioning, Zn isotopes signatures, and multivariate statistics. Zinc and Pb concentrations in Suspended Particulate Matter (SPM) and sediments were considerably higher in some sites. The sediment partition of As, Cr, and Cu revealed the residual fraction (F4) as the main fraction for these elements, indicating low mobility. Zinc and Pb were mostly associated with the exchangeable/carbonate (F1) and the reducible (F2) fractions, respectively, implying a higher susceptibility of these elements to being released from sediments. Zinc isotopic compositions of sediments and SPM fell in a binary mixing source process between lithogenic (δ66/64ZnJMC ≈ + 0.30‰) and anthropogenic (δ66/64ZnJMC ≈ + 0.15‰) end members. The lighter δ66/64ZnJMC values accompanied by high Zn concentrations in exchangeable/carbonate fraction (ZnF1) enable the tracking of Zn anthropogenic sources in the studied rivers. Overall, the results indicated that Hg, Pb, and Zn had a dominant anthropogenic origin linked to the industrial activities, while As, Cr, and Cu were mainly associated with lithogenic sources. This work demonstrates how integrating geochemical tools is valuable for assessing geochemical processes and mixing source effects in anthropized river watersheds.Chromium (Cr) is used in many manufacturing processes, and its release into natural waters is a major environmental problem today. Low concentrations of Cr(VI) are toxic to human health and living organisms due to the carcinogenic and mutagenic nature of this mineral. This work examined the conversion of Cr(VI) to Cr(III) via electrochemical reduction using gold electrode in an acidic sodium alginate (SA) solution and subsequent removal of the produced Cr(III)-SA by the polymer-enhanced ultrafiltration (PEUF) technique. A solution of SA in nitric acid was used both as an electrolytic medium during the voltammetric measurements and bulk electrolysis and as an extracting agent during the PEUF technique. The electroanalysis of Cr(VI) was performed by linear sweep voltammetry in the presence of acidic SA solution to study its voltammetric behavior as a function of the Cr(VI) concentration, pH, presence of Cr(III), SA concentration and scan rate. In addition, the quantitative reduction of Cr(VI) to Cr(III) was studied through the bulk electrolysis technique. The results showed efficient reduction with well-defined peaks at approximately 0.3 V vs. Ag/AgCl, using a gold working electrode. As the pH increased, the reduction signal strongly decreased until its disappearance. The optimum SA concentration was 10 mmol/L, and it was observed that the presence of Cr(III) did not interfere in the Cr(VI) electroanalysis. Through the quantitative reduction by bulk electrolysis in the presence of acidic SA solution, it was possible to reduce all Cr(VI) to Cr(III) followed by its removal via PEUF.Ceria is widely used as a catalyst for soot combustion, but effects of Zr substitution on the reaction mechanism is ambiguous. The present work elucidates effects of Zr substitution on soot combustion over cubic fluorite-structured nanoceria. The nanostructured CeO2, Ce0.92Zr0.08O2, and Ce0.84Zr0.16O2 composed of 5-6 nm crystallites display Tm-CO2 (the temperature at maximum CO2 yield) at 383, 355, and 375°C under 10 vol.% O2/N2, respectively. https://www.selleckchem.com/products/diphenhydramine.html The size of agglomerate decreases from 165.5 to 51.9-57.3 nm, which is beneficial for the soot-ceria contact. Moreover, Zr increases the amount of surface oxygen vacancies, generating more active oxygen (O2- and O-) for soot oxidation. Thus, the activities of Ce0.92Zr0.08O2 and Ce0.84Zr0.16O2 in soot combustion are better than that of CeO2. Although oxygen vacancies promote the migration of lattice O2-, the enriched surface Zr also inhibits the mobility of lattice O2-. Therefore, the Tm-CO2 of Ce0.84Zr0.16O2 is higher than that of Ce0.92Zr0.08O2. Based on reaction kinetic study, soot in direct contact with ceria preferentially decomposes with low activation energy, while the oxidation of isolated soot occurs through diffusion with high activation energy. The obtained findings provide new understanding on the soot combustion over nanoceria.Steel slag (SS) is one of byproduct of steel manufacture industry. The environmental concerns of SS may limit their re-use in different applications. The goal of this study was to investigate the leaching behavior of metals from SS before and after treated by microbially induced carbonate precipitation (MICP). Toxicity characteristic leaching procedure, synthetic precipitation leaching procedure and water leaching tests were performed to evaluate the leaching behavior of major elements (Fe, Mg and Ca) and trace elements (Ba, Cu and Mn) in three scenarios. The concentrations of leaching metals increased with the content of SS. After it reached the peak concentration, the leaching concentration decreased with the content of SS. The leachability of all elements concerned in this study was below 0.5%. The carbonate generated from the MICP process contributed to the low leachability of metals. After bio-modified by MICP process, the leaching concentrations of Ba from TCLP, SPLP and WLT tests were below 2.0 mg/L, which was the limit in drinking water regulated by U.S. EPA. The concentrations of Cu leached out from MICP-treated SS-sand samples were below 1.3 mg/L which is the limit regulated by national secondary drinking water. Compared with the regulations of U.S.EPA and Mississippi Department of Environment Quality (MDEQ), MICP-treated samples were classified as non-hazardous materials with respects to the leaching of metals. Meanwhile, maximum contaminant limits regulated by U.S.EPA states that MICP-treated SS are eco-friendly materials that can be reused as construction materials.
Paste Settings
Paste Title :
[Optional]
Paste Folder :
[Optional]
Select
Syntax Highlighting :
[Optional]
Select
Markup
CSS
JavaScript
Bash
C
C#
C++
Java
JSON
Lua
Plaintext
C-like
ABAP
ActionScript
Ada
Apache Configuration
APL
AppleScript
Arduino
ARFF
AsciiDoc
6502 Assembly
ASP.NET (C#)
AutoHotKey
AutoIt
Basic
Batch
Bison
Brainfuck
Bro
CoffeeScript
Clojure
Crystal
Content-Security-Policy
CSS Extras
D
Dart
Diff
Django/Jinja2
Docker
Eiffel
Elixir
Elm
ERB
Erlang
F#
Flow
Fortran
GEDCOM
Gherkin
Git
GLSL
GameMaker Language
Go
GraphQL
Groovy
Haml
Handlebars
Haskell
Haxe
HTTP
HTTP Public-Key-Pins
HTTP Strict-Transport-Security
IchigoJam
Icon
Inform 7
INI
IO
J
Jolie
Julia
Keyman
Kotlin
LaTeX
Less
Liquid
Lisp
LiveScript
LOLCODE
Makefile
Markdown
Markup templating
MATLAB
MEL
Mizar
Monkey
N4JS
NASM
nginx
Nim
Nix
NSIS
Objective-C
OCaml
OpenCL
Oz
PARI/GP
Parser
Pascal
Perl
PHP
PHP Extras
PL/SQL
PowerShell
Processing
Prolog
.properties
Protocol Buffers
Pug
Puppet
Pure
Python
Q (kdb+ database)
Qore
R
React JSX
React TSX
Ren'py
Reason
reST (reStructuredText)
Rip
Roboconf
Ruby
Rust
SAS
Sass (Sass)
Sass (Scss)
Scala
Scheme
Smalltalk
Smarty
SQL
Soy (Closure Template)
Stylus
Swift
TAP
Tcl
Textile
Template Toolkit 2
Twig
TypeScript
VB.Net
Velocity
Verilog
VHDL
vim
Visual Basic
WebAssembly
Wiki markup
Xeora
Xojo (REALbasic)
XQuery
YAML
HTML
Paste Expiration :
[Optional]
Never
Self Destroy
10 Minutes
1 Hour
1 Day
1 Week
2 Weeks
1 Month
6 Months
1 Year
Paste Status :
[Optional]
Public
Unlisted
Private (members only)
Password :
[Optional]
Description:
[Optional]
Tags:
[Optional]
Encrypt Paste
(
?
)
Create New Paste
You are currently not logged in, this means you can not edit or delete anything you paste.
Sign Up
or
Login
Site Languages
×
English
Tiếng Việt
भारत