Integrated electrokinetic processes for the remediation of phthalate esters in river sediments: A mini-review.

Concerning the contamination of phthalate esters (PAEs) in river sediments, this mini-review introduces four recently reported novel "integrated electrokinetic (EK) processes" for the remediation purpose, namely two combined technologies of the EK process and advanced oxidation process (EK-AOP Processes) and two combined technologies of the EK process and biological process (EK-BIO Processes). The following is a comprehensive summary for these remediation processes: (1) the EK process coupled with nano-FeO/SO oxidation process - Test results have shown that nanoscale FeO played a significant role in activating persulfate oxidation. Even a recalcitrant compound like di(2‑ethylhexyl)phthalate (DEHP), its concentration in test sediment was reduced to 1.

Removal of micropollutants from municipal wastewater by graphene adsorption and simultaneous electrocoagulation/electrofiltration process.

In this work the optimal operating conditions for removing selected micropollutants (also known as emerging contaminants, ECs) from actual municipal wastewater by graphene adsorption (GA) and simultaneous electrocoagulation/electrofiltration (EC/EF) process, respectively, were first determined and evaluated. Then, performance and mechanisms for the removal of selected phthalates and pharmaceuticals from municipal wastewater simultaneously by the GA and EC/EF process were further assessed. ECs of concern included di-n-butyl phthalate (DnBP), di-(2-ethylhexyl) phthalate (DEHP), acetaminophen (ACE), caffeine (CAF), cefalexin (CLX) and sulfamethoxazole (SMX).

Achieving zero waste of municipal incinerator fly ash by melting in electric arc furnaces while steelmaking.

The main objective of this work was to promote zero waste of municipal incinerator fly ash (MIFA) by full-scale melting in electric arc furnaces (EAFs) of steel mini mills around the world. MIFA, generally, is considered as a hazardous waste. Like in many countries, MIFA in Taiwan is first solidified/stabilized and then landfilled.

Biocompatibility assessment of nanomaterials for environmental safety screening.

In view of the extensive use of nanoparticles in countless applications, a fast and effective method for assessing their potential adverse effects on the environment and human health is extremely important. At present, in vitro cell-based assays are the standard approach for screening chemicals for cytotoxicity because of their relative simplicity, sensitivity, and cost-effectiveness compared with animal studies. Regrettably, such cell-based viability assays encounter limitations when applied to determining the biological toxicity of nanomaterials, which often interact with assay components and produce unreliable outcomes.

Degradation of phthalate esters and acetaminophen in river sediments using the electrokinetic process integrated with a novel Fenton-like process catalyzed by nanoscale schwertmannite.

The main objective of this study was to develop and establish an in situ remediation technology coupling nano-schwertmannite/H2O2 process and electrokinetic (EK) process for the removal of phthalates (PAEs) and acetaminophen in river sediments. Test results are given as follows: (1) injection of nano-schwertmannite slurry and H2O2 (collectively, "novel oxidant") into the anode reservoir would yield ·OH radicals that then will be diffused into the sediment compartment and further transported by the electroosmotic flow and/or electrophoresis from the anode end toward the cathode to degrade PAEs and pharmaceuticals in the sediment if any; (2) an electric potential gradient of 1.5 V cm(-1) would help the removal of PAEs and acetaminophen in the blank test, which no "novel oxidants" was added to the remediation system; (3) the practice of electrode polarity reversal would maintain neutral pH for sediment after remediation; (4) injection of equally divided dose of 10 mL novel oxidant into the anode reservoir and four injection ports on the top of sediment chamber would further enhance the removal efficiency; and (5) an extension of treatment time from 14 d to 28 d is beneficial to the removal efficiency as expected.

Removal of phthalates and pharmaceuticals from municipal wastewater by graphene adsorption process.

In this work graphene was used for evaluation of its adsorption behavior and performance in removing phthalate esters and pharmaceuticals in municipal wastewater. Di-n-butyl phthalate (DnBP), di-(2-ethylhexyl) phthalate (DEHP), acetaminophen (ACE), caffeine (CAF), cephalexin (CLX), and sulfamethoxazole (SMX) were emerging contaminants (ECs) with detection frequencies over 92% in a one-year monitoring of the occurrence of ECs in influent samples of a sewage treatment plant in Taiwan. Thus, these ECs were selected as the target contaminants for removal by graphene adsorption process.

Performance and mechanisms for the removal of phthalates and pharmaceuticals from aqueous solution by graphene-containing ceramic composite tubular membrane coupled with the simultaneous electrocoagulation and electrofiltration process.

In this study, commonly detected emerging contaminants (ECs) in water, including di-n-butyl phthalate (DnBP), di(2-ethylhexyl) phthalate (DEHP), cephalexin (CLX), sulfamethoxazole (SMX) and caffeine (CAF), were selected as the target contaminants. A lab-prepared graphene-containing ceramic composite tubular membrane (TGCCM) coupled with the simultaneous electrocoagulation and electrofiltration process (EC/EF) in crossflow filtration mode was used to remove target contaminants in model solution. Meanwhile, a comparison of the removal efficiency was made among various tubular composite membranes reported, including carbon fibers/carbon/alumina composite tubular membrane (TCCACM), titania/alumina composite tubular membrane (TTACM) and alumina tubular membrane (TAM).

Remediation of phthalates in river sediment by integrated enhanced bioremediation and electrokinetic process.

The objective of this study was to evaluate the feasibility of enhanced bioremediation coupling with electrokinetic process for promoting the growth of intrinsic microorganisms and removing phthalate esters (PAEs) from river sediment by adding an oxygen releasing compound (ORC). Test results are given as follows: Enhanced removal of PAEs was obtained by electrokinetics, through which the electroosmotic flow would render desorption of organic pollutants from sediment particles yielding an increased bioavailability. It was also found that the ORC injected into the sediment compartment not only would alleviate the pH value variation due to acid front and base front, but would be directly utilized as the carbon source and oxygen source for microbial growth resulting in an enhanced degradation of organic pollutants.

Occurrence of triclosan in the tropical rivers receiving the effluents from the hospital wastewater treatment plant.

The objective of this study was to determine the occurrence of triclosan in the tropical rivers where received the effluents from a hospital wastewater treatment plant (HWWTP) in southern Taiwan. Three and ten sampling sites were selected at the Jiaosu River (S0-S2) and Dian-Bao River (S3-S12), respectively. The samples of the HWWTP influent, effluent and receiving river water and sediment were collected and analyzed using ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/ MS).

Monitoring and removal of residual phthalate esters and pharmaceuticals in the drinking water of Kaohsiung City, Taiwan.

This study monitored the occurrence and removal efficiencies of 8 phthalate esters (PAEs) and 13 pharmaceuticals present in the drinking water of Kaohsiung City, Taiwan. The simultaneous electrocoagulation and electrofiltration (EC/EF) process was used to remove the contaminants. To this end, a monitoring program was conducted and a novel laboratory-prepared tubular carbon nanofiber/carbon/alumina composite membrane (TCCACM) was incorporated into the EC/EF treatment module (collectively designated as "TCCACM-EC/EF treatment module") to remove the abovementioned compounds from water samples.

Monitoring of PAEMs and beta-agonists in urine for a small group of experimental subjects and PAEs and beta-agonists in drinking water consumed by the same subjects.

This 5-month study contains two parts: (1) to monitor the concentrations of 11 phthalate esters metabolites (PAEMs) and two beta-agonists in human urine samples collected from a small group of consented participants including 16 females and five males; and (2) to analyze the residues of phthalate esters (PAEs) and beta-agonists in various categories of drinking water consumed by the same group of subjects. Each category of human urine and drinking water had 183 samples of its own. The analytical results showed that nine PAEMs were detected in human urine and eight PAEs were detected in drinking water samples.

Electrokinetically enhanced removal and degradation of nitrate in the subsurface using nanosized Pd/Fe slurry.

The aim of this work was to evaluate the effectiveness of transporting the slurry of Pd/Fe bimetallic nanoparticles under an electric field in the subsurface for in situ removal and degradation of nitrate. To mimic the subsurface environment, a bench-scale horizontal column packed with nitrate-contaminated soil was treated by electrokinetic (EK) remediation coupled with the injection of nanosized Pd/Fe slurry. The estimated transport distance of Pd/Fe nanoparticles in soil based on the calculated sticking coefficient was about 9 meters by the enhancement of electrokinetics, primarily by electroosmotic (EO) flow.

Chemical reduction of nitrate by nanosized iron: kinetics and pathways.

This study was conducted to investigate chemical reduction of nitrate by nanoscale zero-valent iron (ZVI) in aqueous solution and related kinetics and pathways. In the last decade, employment of micro-scale ZVI has gained its popularity in nitrate reduction. To further study chemical reduction of nitrate, nanosized iron was synthesized and tested in this work.

Crossflow electro-microfiltration of oxide-CMP wastewater.

In this work, an electrically enhanced crossflow microfiltration (EECMF) system was used for the treatment of oxide-CMP wastewater under different operating conditions to investigate their effects on filtration rate. Oxide-CMP wastewater was obtained from a wafer fab and characterized by various standard methods. A membrane with a cut size of 0.