Solid peroxy compounds have been increasingly applied for the removal of organic pollution from contaminated groundwater and soil due to their ability to release oxygen and hydrogen peroxide. The influence of two solid peroxy compounds (sodium percarbonate, 2Na2CO3·3H2O2 and calcium peroxide, CaO2) with poultry manure (PM) added to contaminated soil on the growth of the tested plants (Sinapis alba, Lepidium sativum L. and Sorghum bicolor L. Moench) and the quality of soil water leachates was investigated. A series of experiments involving the addition of CaO2 and 2Na2CO3·3H2O2 at the dose of 0.075 g/g PM improved the growth of tested plants. The conducted study indicated that the use of peroxy compounds not only removed pathogens from livestock waste, but also improved the quality of plant growth. The calculated factors for the growth of roots (GFR) and growth of shoots (GFS) in soils treated with a mixture of peroxy compounds and PM were higher than in soils treated only with PM. The physicochemical analysis of soil water leachates indicated that solid peroxy compounds may be a promising alternative compared to the currently used hygienizing agent such as calcium hydroxide (Ca(OH)2). Solid peroxy compounds increased the bioavailability of components necessary for proper seed germination and plant growth (N, P, K, Ca, Mg and S). In most of the studied cases, the obtained plant shoot and root growth rates were higher for soil mixtures containing organic waste deactivated by biocidal compounds, compared to soils that contained only poultry manure.

In this work, the novel application of chalcopyrite (CuFeS2) for sodium percarbonate (SPC) activation towards sulfamethazine (SMT) degradation was explored. Several key influencing factors like SPC concentration, CuFeS2 dosage, reaction temperature, pH value, anions, and humic acid (HA) were investigated. Experimental results indicated that SMT could be effectively degraded in the neutral reaction media by CuFeS2/SPC process (86.4%, 0.054 min-1 at pH = 7.1). The mechanism of SPC activation by CuFeS2 was elucidated, which was discovered to be a multiple reactive oxygen species (multi-ROS) process with the coexistence of hydroxyl radical (•OH), carbonate radical (CO3•-), superoxide radical (O2•-), and singlet oxygen (1O2), as evidenced by quenching experiments and electron spin resonance (ESR) tests. The generated •OH via the traditional heterogeneous Fenton-like process would not only react with carbonate ions to yield other ROS but also involve in SMT degradation. The abundant surface-bound Fe(II) was deemed to be the dominant catalytic active sites for SPC activation. Meanwhile, it was verified that the reductive sulfur species, the interaction between Cu(I) and Fe(III) as well as the available O2•- derived from the activation of molecular oxygen and the conversion of •OH favored the regeneration of Fe(II) on CuFeS2 surface. Furthermore, the degradation intermediates of SMT and their toxicities were evaluated. This study presents a novel strategy by integrating transition metal sulfides with percarbonate for antibiotic-contaminated water treatment.

Sodium percarbonate (SPC) and peroxymonocarbonate (PMC) have been widely used in modified Fenton reactions because of their multiple superior features, such as a wide pH range and environmental friendliness. This broad review is intended to provide the fundamental information, status and progress of SPC and PMC based decontamination technologies according to the peer-reviewed papers in the last two decades. Both SPC and PMC can directly decompose various pollutants. The degradation efficiency will be enhanced and the target contaminants will be expanded after the activation of SPC and PMC. The most commonly used catalysts for SPC activation are iron compounds while cobalt compositions are applied to activate PMC in homogenous and heterogeneous catalytical systems. The generation and participation of hydroxyl, superoxide and/or carbonate radicals are involved in the activated SPC and PMC system. The reductive radicals, such as carbon dioxide and hydroxyethyl radicals, can be generated when formic acid or methanol is added in the Fe(II)/SPC system, which can reduce target contaminants. SPC can also be activated by energy, tetraacetylethylenediamine, ozone and buffered alkaline to generate different reactive radicals for pollutant decomposition. The SPC and activated SPC have been assessed for application in-situ chemical oxidation and sludge dewatering treatment. The challenges and prospects of SPC and PMC based decontamination technologies are also addressed in the last section.

The increasing frequency and intensity of blooms of toxin- and taste & odour-producing filamentous cyanobacteria in water sources is a growing global issue. Compared to the common spherical Microcystis genus, the removal of filamentous cyanobacteria is more difficult in drinking water treatment plants; hence, abatement and control of the occurrence and proliferation of harmful filamentous cyanobacteria within drinking water sources is important for water supply. In this study, the solid sodium percarbonate (SPC), Na2CO3·1.5H2O2, was used as an algaecide to eliminate the cyanobacteria distributed throughout the water column in the surface and bottom layer of a reservoir serving as a drinking water source. Results showed that although the oxidation capacity of SPC was higher in the surface water due to the higher light intensity than in the bottom water, 3.0 mg/L SPC can still suppress the harmful cyanobacteria in the bottom water after 36 h because the carbonate ion generated by SPC decomposition can act as an activator of H2O2 to generate many reactive oxygen species - including superoxide radicals, carbonate radical anions, and hydroxyl radicals - even in the light-limited environment. The obtained inactivation rates for the main cyanobacteria in this reservoir followed the order: Pseudanabaena limnetica > Raphidiopsis curvata > Cylindrospermopsis raciborskii. 3.0 mg/L SPC has a slight impact on microeukaryotic communities according to the 18S rRNA gene sequencing, while 6.0 mg/L SPC changed the composition of eukaryotic phytoplankton and zooplankton clearly. Eukaryotic co-occurrence networks showed that although the network of eukaryotic plankton in treated surface water was more compact and clustered, stability of microeukaryotes in the treated surface water was lower than for the treated bottom water, owing to the higher oxidation capacity of SPC in the surface water. The results above not only have important implications for full-scale control of harmful cyanobacteria in drinking water sources, especially filamentous cyanobacteria with vertical distributions, but also help to ensure the health and stability of the whole aquatic ecosystem.

Leachate generated in landfills are characterized by high toxicity related to, high concentrations of organic and non-organic pollutants, therefore, it is advisable to use highly effective methods of their purification to prevent environmental contamination. The aim of this study was to determine the treatment efficiency of landfill leachate during the application of integrated processes: advanced oxidation (AOP) and biochar adsorption (BC). In the case of the AOP, the chemical process was the Fenton reaction in which the source of hydroxyl radicals was H2O2 (system I) and SPC - sodium percarbonate (system II). Leachate was derived from the regional municipal waste landfill in Silesian Province (Poland) which was characterized by the pH of 8.40, COD value was 3155 mg L-1 and BOD was under 165 mg L-1. The BOD/COD ratio was at a low level (0.053) that indicated low biodegradability. The applied systems allowed of the COD reduction index to the level of 549 mg L-1 (H2O2+BC) and 944 mg L-1 (SPC+BC) where the limit threshold is 125 mg L-1. In the same case of the TOC index, these values were respectively 119 and 186 mg L-1, where the limit value is 30 mg L-1.This study has been aimed to estimate the toxicity of leachate treatment in integrated systems: AOP processes + biochar adsorption. Toxicity of treated and untreated leachate has been analysed by Sinapis alba and Lepidium sativum plants-based tests. It was found that while conducting the Fenton process as system I (H2O2) at all reagent doses, the removal efficiency of COD and TOC was 17% and 12% higher, respectively, compared to system II. The most advantageous dose of regents was 2.5:1 and biochar - 2 g L-1. It was observed that in the SPC+BC system the roots of L. sativum and S. alba were on average 34% and 28% longer compared to the H2O2+BC system. Higher germination index (GI) of both tested plants, indicating lower wastewater toxicity, was recorded for the SPC+BC system.

Sodium percarbonate (SPC, 2Na2CO3∙3H2O2), is a compound that can be used under multiple environmental applications. In this work, SPC was employed as oxidant in the treatment of soil contaminated with diesel oil. The soil samples were collected during the earthmoving stage of RNEST Oil Refinery (Petrobras), Brazil. Then, the samples were air-dried, mixed and characterized. Subsequently, raw soil was contaminated with diesel and treated by photo-Fenton reaction (H2O2/Fe2+/UV). SPC played a significant role in the generation of hydroxyl radicals under the catalytic effect of ferrous ions (Fe2+), hydrogen peroxide (H2O2) and radiation. These radicals provoked the photodegradation of polycyclic aromatic hydrocarbons (PAHs), in the soil remediation. A factorial design 33 was carried out to assess the variables which most influenced the decrease in total organic carbon (TOC). The study was performed with the following variables: initial concentration of [H2O2] and [Fe2+], between 190.0 and 950.0 mmol L-1 and 0.0-14.4 mmol L-1, respectively. UV radiation was supplied from sunlight, blacklight lamps, and system without radiation. All experiments were performed with 5.0 g of contaminated soil in 50.0 mL of solution. The initial concentration of Fe2+ showed the statistically most significant effect. The oxidation efficiency evaluated in the best condition showed a decrease from 34,765 mg kg-1 to 15,801 mg kg-1 in TOC and from 85.750 mg kg-1 to 20.770 mg kg-1 in PAHs content. Moreover, the sums of low and high molecular weight polycyclic aromatic hydrocarbons (LMW-PAHs and HMW-PAHs) were 19.537 mg kg-1 and 1.233 mg kg-1, respectively. Both values are within the limits recommended by the United Sates Environmental Protection Agency (USEPA) and evidenced the satisfactory removal of PAHs from contaminated soil, being an alternative to classic oxidation protocols.

4-Nonylphenol (4-NP), a phenolic endocrine disruptor chemical (EDC), is known to have high toxicity to aquatic organisms and humans. The remediation of 4-NP-contaminated marine sediments was studied using red algae-based biochar (RAB) thermochemically synthesized from Agardhiella subulata with simple pyrolysis process under different temperatures of 300-900 °C in CO2 atmosphere. The RAB was characterized by XRD, Raman, FTIR spectroscopy, and zeta potential measurements. The calcium in RAB efficiently activated sodium percarbonate (SPC) to generate reactive radicals for the catalytic degradation of 4-NP at pH 9.0. The oxygen-containing functional groups reacted with H2O2, which increased the generation of reactive radicals under alkaline pH condition. Ca2+ ion was the active species responsible for 4-NP degradation. CaO/CaCO3 on RAB surface enhanced direct electron transfer, increased HO production, and 4-NP degradation in marine sediments. Langmuir‒Hinshelwood type kinetics well described the 4-NP degradation process. Remediation of contaminated sediments using RAB could be a sustainable approach toward closed-loop biomass cycling in the degradation of 4-NP contaminants.

The performance of trichloroethylene (TCE) degradation by sodium percarbonate (SPC) activated with Fe(II) in the presence of 3.0 g/L sodium dodecyl sulfate (SDS) as well as the role of SDS in the SPC/Fe(II) system was investigated since SDS is a common surfactant used in groundwater remediation for improving TCE dissolution to the aqueous phase. The results showed that though the introduction of SDS could inhibit the TCE degradation, the inhibiting effect was less with the increasing SDS dose. In the presence of SDS, TCE could be completely removed with the SPC/Fe(II)/TCE molar ratio of 40/80/1. Experiments with free radical probe compounds and radical scavengers elucidated that TCE was mainly oxidized by both HO· and O 2 - · . A weakly acidic environment was more favorable to TCE degradation. Nevertheless, HCO 3 - at a high concentration had a strongly inhibitive effect on the TCE degradation but the influence of Cl- was negligible. Finally, the excellent TCE degradation achieved in actual groundwater demonstrated that Fe(II) activated SPC technique was applicable in the remediation of TCE contaminated groundwater in the presence of SDS. PRACTITIONER POINTS: The effects of SDS were evaluated SPC/Fe(II)/SDS system applied to remediate TCE The mechanism of HO· and O 2 - · generation had been investigated Cl- and HCO 3 - affected TCE degradation at different levels The performance of TCE removal in actual groundwater had been studied.

Laundering clothes with modern detergents containing sodium percarbonate can result in false negative results when certain presumptive and confirmatory tests are used to detect the presence of blood. This is problematic as blood evidence can be inadvertently overlooked and criminal activity concealed, simply by laundering bloodstained clothes in detergent. The aim of this research was to determine if the incidence of positive results using tetramethylbenzidine (TMB) reagent, luminol, Bluestar® Magnum, ABAcard® Hematrace® and RSID™-Blood was affected by treatment in hot and cold water, with and without the detergent, sodium percarbonate. This study identified that RSID-Blood consistently produced positive results irrespective of water temperature or the addition of sodium percarbonate. All other reagents returned positive results in the absence of sodium percarbonate, regardless of water temperature. The introduction of sodium percarbonate initiated negative results regardless of water temperature when testing with tetramethylbenzidine reagent, Bluestar® Magnum and ABAcard® Hematrace®. Luminol in the presence of sodium percarbonate responded differently to the temperature change of the water. Cold water returned positive results, however, hot water returned negative results. This research indicates that RSID™-Blood surpassed other blood screening tests identifying blood on sodium percarbonate treated cotton fabric. The results for luminol were varied depending on water temperature, however, luminol performed better as a presumptive test than TMB or Bluestar® Magnum.

A coupling technique introducing sodium percarbonate (SPC) into a dielectric barrier discharge (DBD) plasma was investigated to enhance the degradation of antibiotic tetracycline (TC) in aqueous. The dominant effects of SPC addition amount and discharge voltage were evaluated firstly. The experiments indicated that the moderate SPC dosages in the DBD presented an obvious synergistic effect, improving the TC decomposition efficiency and kinetics. Elevating the voltage was conducive for the promotion of antibiotic abatement. After 5 min treatment, the removal reached 94.3% at the SPC of 52.0 μmol/L and voltage of 4.8 kV for 20 mg/L TC. Especially the defined synergy factors were greater than one since the SPC being added, and the energy yield was increased by 155%. Besides, the function mechanism was explained by the hydrogen peroxide and ozone quantitative determinations and radical scavenger test, and the results confirmed that the collaborative method could increase the generation of reactive species, and the produced hydroxyl and superoxide radicals both played the significant roles for the TC elimination. Furthermore, the decomposition and mineralization of the synergism were verified by UV-vis spectroscopy, TOC and COD analyses, and the degradation byproducts and transformation pathways were identified based on the analysis of HPLC-MS finally.