Preferential Adsorption of Prominent Amino Acids in the Urease Enzyme of on Arid Soil Components: A Periodic DFT Study.

The urease enzyme is commonly used in microbially induced carbonate precipitation (MICP) and enzyme-induced carbonate precipitation (EICP) to heal and strengthen soil. Improving our understanding of the adsorption of the urease enzyme with various soil surfaces can lead to advancements in the MICP and EICP engineering methods as well as other areas of soil science. In this work, we use density functional theory (DFT) to investigate the urease enzyme's binding ability with four common arid soil components: quartz, corundum, albite, and hematite.

A laboratory preparation procedure for studying bioaccumulation of U and its subcellular form in earthworms ( spp.).

Uranium (U) is a ubiquitous trace element in soils. With increasing in application of U in nuclear energy and nuclear weapon, a large amount of U was dissipated into the environment including soil and water. Earthworm may be an eco-indicator for U bioaccumulation, transformation and transport across the ecosystem.

A laboratory simulation to investigate effects of moistures on U distribution among solid phase components in army range soils.

Uranium is a naturally occurring radioactive trace element found in rocks, soils, and coals. U may contaminate groundwater and soil from nuclear power plant operations, spent fuel reprocessing, high-level waste disposal, ore mining and processing, or manufacturing processes. Yuma Proving Ground in Arizona, USA has been used depleted uranium ballistics for 36 years where U has accumulated in this army testing site.

The Adsorption Characteristics of Uranium(VI) from Aqueous Solution on Leonardite and Leonardite-Derived Humic Acid: A Comparative Study.

The humic substance is a low-cost and effective adsorbent with abundant functional groups in remediating uranium (U) (VI)-contaminated water. In this research study, leonardite together with leonardite-derived humic acid (L-HA) was used to eliminate U(VI) from water under diverse temperatures (298, 308, and 318 K). L-HA showed a higher adsorption volume for U(VI) than leonardite.

Functionalization of clay surface for the removal of uranium from water.

A modification method of clay mineral surface was developed to improve its adsorption capacity of uranium. Uranium is a radionuclide with high toxicity and extremely long half-life, which can pollute the environment and endanger human health. This study proposes a new method of activation of clay mineral surface with phosphoric acid for rapid adsorption of uranium from aqueous solution.

Amendment for increased methane production rate in municipal solid waste landfill gas collection systems.

Optimization of methane production rate can potentially decrease the operational lifetime of the landfill site and assist with better management of methane harvesting from the landfill cells. Increased moisture content in landfill cells is known to increase the rate of methane production. Several natural biopolymers can sustain moisture content in a solid matrix while providing a scaffolding for microbial communities to grow.

A simple method for the synthesis of biochar nanodots using hydrothermal reactor.

Biochar is a stable carbon rich by-product synthesized through pyrolysis of plant and animal based biomass, and nano-biochar material has gained increasing attention due to its unique properties for environmental applications. In the present study, a simple cost-effective method for the synthesis of biochar nanoparticles through hydrothermally using agricultural residuals and by-products was developed. Both soybean straw and cattle manure were selected as the feedstock to produce the bulk-biochar.

Laboratory simulation of uranium metal corrosion in different soil moisture regimes.

A novel laboratory simulation system has been developed for the study of the corrosion of uranium metal in soils. Corrosion and transportation of depleted uranium (DU) as the metal undergoes weathering as a buried material within the soil environment. The corrosion of uranium metal in soil was not well understood due to the gas-liquid-solid phase of the soil.

A novel laboratory simulation system to uncover the mechanisms of uranium upward transport in a desert landscape.

After depleted uranium (DU) is deposited in the environment, it corrodes producing mobile uranium species. The upward transport mechanism in a desert landscape is associated with the dissolution/precipitation of uranium minerals that vary in composition and solubility in soil pore water. The objective of this study is to develop the laboratory column simulation to investigate the upward transport mechanism with cyclic capillary wetting and drying moisture regimes.

Electrokinetic-enhanced phytoremediation of uranium-contaminated soil using sunflower and Indian mustard.

Electrokinetic-enhanced phytoremediation is an effective technology to decontaminate heavy metal contaminated soil. In this study, we examined the effects of electrokinetic treatments on plant uptake and bioaccumulation of U from soils with various U sources. Redistribution of uranium in soils as affected by planting and electrokinetic treatments was investigated.

Kinetics and Thermodynamics of Uranium (VI) Adsorption onto Humic Acid Derived from Leonardite.

Humic acid (HA) is well known as an inexpensive and effective adsorbent for heavy metal ions. However, the thermodynamics of uranium (U) adsorption onto HA is not fully understood. This study aimed to understand the kinetics and isotherms of U(VI) adsorption onto HA under different temperatures from acidic water.

Laboratory spiking process of soil with various uranium and other heavy metals.

Laboratory studies using metal spiked soils are challenging due to soil heterogeneity. This work provides an easy, quick, precise, and accurate technique for the preparation of spiked soils for laboratory research. The process described spiking soil with various uranium species and other heavy metals for laboratory scale pilot experiments under various biogeochemical conditions.

Removing uranium (VI) from aqueous solution with insoluble humic acid derived from leonardite.

The occurrence of uranium (U) and depleted uranium (DU)-contaminated wastes from anthropogenic activities is an important environmental problem. Insoluble humic acid derived from leonardite (L-HA) was investigated as a potential adsorbent for immobilizing U in the environment. The effect of initial pH, contact time, U concentration, and temperature on U(VI) adsorption onto L-HA was assessed.

Bullet on bullet fragmentation profile in soils.

Lead-antimony alloy slugs encased in a brass jackets are common small arms caliber ammunition used for training and target practice. When small caliber ammunition is fired at testing and training ranges, these metals--some of which are toxic--are introduced into the environment. Research was conducted on the effects of bullet on bullet impacts and the resulting bullet fragmentation.

Hydrolysis of the soluble fluorescent molecule carboxyumbelliferyl-beta-D-glucuronide by E. coli beta-glucuronidase as applied in a rugged, in situ optical sensor.

Techniques utilizing β-glucuronidase (GUS) activity as an indicator of Escherichia coli (E. coli) presence use labeled glucuronides to produce optical signals. Carboxyumbelliferyl-β-d-glucuronide (CUGlcU) is a fluorescent labeled glucuronide that is soluble and highly fluorescent at natural water pHs and temperatures and, therefore, may be an ideal reagent for use in an in situ optical sensor.

The effect of phosphate application on the mobility of antimony in firing range soils.

Chemical and biogenic sources of phosphate are commonly accepted in situ treatment methods for immobilization of lead (Pb) in soil. The metalloid antimony (Sb), commonly associated with Pb in the environment, exists as either a neutral species or a negatively charged oxyanion. Antimony is used in the manufacture of bullets as a hardening agent, constituting approximately 3% of the bullet mass.

Dissolution, sorption, and kinetics involved in systems containing explosives, water, and soil.

Knowledge of explosives sorption and transformation processes is required to ensure that the proper fate and transport of such contaminants is understood at military ranges and ammunition production sites. Bioremediation of 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), and related nitroaromatic compounds has met with mixed success, which is potentially due to the uncertainty of how energetic compounds are bound to different soil types. This study investigated the dissolution and sorption properties of TNT and RDX explosives associated with six different soil types.

Applicability of alkaline hydrolysis for remediation of TNT-contaminated water.

This study was conducted to assess the applicability of alkaline hydrolysis as an alternative ex situ technology for remediating 2,4,6-trinitrotoluene (TNT)-contaminated water. TNT reactivity had a strong dependence on the reaction pH (11-12) and initial TNT (5-25 mg L(-1)) in batch systems, resulting in pseudo first-order transformation rate, k ranging between 1.9 x 10(-3) and 9.

Perchlorate analysis using solid-phase extraction cartridges.

Perchlorate is a compound of increasing concern as an environmental contaminant and is being regulated at increasingly stringent levels. Reliable methods are needed to consistently analyze perchlorate at low concentration levels. This research investigates the use of solid-phase extraction cartridges as an alternative to large-volume injection loops to achieve low-level (microg/L level) perchlorate quantitation.

Bench- and field-scale evaluation of chromium and cadmium extraction by electrokinetics.

The results of bench-scale laboratory tests and in situ, pilot-scale demonstration of electrokinetic extraction of chromium and cadmium from contaminated soil are presented. The laboratory tests were conducted using 10 cm long samples under current density of 5A/m(2) for 1200 h. Tests were conducted with and without citric acid amendment at the cathode.

Decolorization of alkaline TNT hydrolysis effluents using UV/H(2)O(2).

Effects of H(2)O(2) dosage (0, 10, 50, 100 and 300 mg/l), reaction pH (11.9, 6.5 and 2.

Treatment of trinitrotoluene by crude plant extracts.

Crude plant extract solutions (spinach and parrotfeather) were prepared and spiked with 2,4,6-trinitrotoluene (TNT) (20 mgl(-1)). 90-h TNT removal by these solutions was compared to controls. Spinach and parrotfeather extract solutions removed 99% and 50% of the initial TNT, respectively; TNT was not eliminated in the controls or in extract solutions where removal activity was deactivated by boiling.

Treatment of munitions in soils using phytoslurries.

Phytoremediation is an established technology for the treatment of explosives in water and soil. This study investigated the possibility of using slurried plants (or phytoslurries) to treat explosives (TNT and RDX). The degradation of TNT in solution using intact and slurried parrotfeather (Myriophyllum aquaticum), spinach (Spinicia oleracea), and mustard greens (Brassica juncea) was evaluated.

UV-VIS spectroscopy of 2,4,6-trinitrotoluene-hydroxide reaction.

Contamination of groundwater, surface water and soil by explosives has occurred at military sites throughout the world as a result of manufacture of explosive compounds, assembly of munitions, and deployment of explosives containing devices. Due to the adverse effects of explosives on humans and other natural receptors, a low cost means of decontaminating these areas of contamination is needed. Base-induced transformation of explosives has shown promise as a rapid, low cost, and minimally resource-intensive technology for detoxifying explosives in soil and water.

Analysis of CL-20 in environmental matrices: water and soil.

Analytical techniques for the detection of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazatetracyclo(5.5.0.