Efficiency Of Photolysis Research Articles

Design, Synthesis, and Photochemical Properties of Gene‐directed Caged RyR Probes for Photopharmacological Studies

AbstractRyanodine receptor (RyR) is a crucial intracellular Ca2+ channel involved in various physiological processes associated with several diseases. This paper presents the synthesis and evaluation of novel photoactivatable caged compounds for the RyR. We used (6‐bromo‐7‐hydroxycoumarn‐4‐yl)methyl (Bhc) as the photolabile protecting group to develop caged versions of 4‐CmC, a broad‐spectrum RyR agonist, and FLA365, an antagonist. The synthesized compounds, Bhcmoc‐4‐CmC and Bhcmoc‐FLA365, exhibited photoreactivity that enabled spatiotemporal control over the RyR activity. Bhcmoc‐4‐CmC presents a quantum yield of 25 % and a photolysis efficiency of 1,075 M−1 cm−1 under 405 nm light, triggering Ca2+ release from the endoplasmic reticulum. Conversely, Bhcmoc‐FLA365 presents a reduced quantum yield of 0.61 %, which can be attributed to the quenching effects of its tertiary amine structure. We also applied gene‐directed caging, synthesizing β‐galactosidase (β‐Gal) activatable Gal‐Bhcmoc‐4‐CmC and Gal‐Bhcmoc‐FLA365, and porcine liver esterase (PLE)‐activatable CM‐Bhcmoc‐FLA365, to target these probes to the specific cell types. These caged compounds contribute significantly to photopharmacology, providing tools for the precise analysis and manipulation of the RyR functions. Future research objectives involve further optimization and analysis of the photochemical mechanisms of these caged compounds to enhance their applications in biological and medical research.

In Search of Visible Light Activatable Photocages: Structure‐Activity Relationship Study on C‐8 Substituted Indene‐Fused‐Coumarinyl Photoremovable Protecting Groups

AbstractA series of C‐8 substituted indeno[1,2‐g]coumarin‐based photoremovable protecting groups (PPGs) were synthesized. para‐Substituted benzoic acids were employed as leaving groups to evaluate their photolytic efficiency. Substitution of phenyl groups was proved to have negative impacts on photochemical properties of the PPGs, including but not limited to: retarded photolysis course, decreased uncaging quantum yield, and unsatisfactory cargo release yield. Electron‐donating diethylamino substituted PPG 3 d, a structural analogue of the widely used 7‐diethylaminocoumarin PPG (DEACM), exhibited red‐shifted absorption maximum and improved optical properties. Photochemical characterization revealed that PPG 3 d not only showed comparable photolytic efficiency to DEACM at 365 nm and 405 nm, but also demonstrated superior sensitivity towards 465 nm wavelength, to which DEACM is unable to absorb and therefore, non‐responsive. The >450 nm photosensitivity makes 3 d a complement to DEACM for long wavelength excitation and a promising PPG for biological applications.

Technical Note: A technique to convert NO2 to NO2− with S(IV) and its application to measuring nitrate photolysis

Abstract. Nitrate photolysis is a potentially significant mechanism for “renoxifying” the atmosphere, i.e., converting nitrate into nitrogen oxides – nitrogen dioxide (NO2) and nitric oxide (NO) – and nitrous acid (HONO). Nitrate photolysis in the environment occurs through two channels which produce (1) NO2 and hydroxyl radical (⚫OH) and (2) nitrite (NO2-) and an oxygen atom (O(3P)). Although the aqueous quantum yields and photolysis rate constants of both channels have been established, field observations suggest that nitrate photolysis is enhanced in the environment. Laboratory studies investigating these enhancements typically only measure one of the two photo-channels, since measuring both channels generally requires separate analytical methods and instrumentation. However, measuring only one channel makes it difficult to assess whether secondary chemistry is enhancing one channel at the expense of the other or if there is an overall enhancement of nitrate photochemistry. Here, we show that the addition of S(IV), i.e., bisulfite and sulfite, can convert NO2 to NO2-, allowing for measurement of both nitrate photolysis channels with the same equipment. By varying the concentration of S(IV) and exploring method parameters, we determine the experimental conditions that quantitatively convert NO2 and accurately quantify the resulting NO2-. We then apply the method to a test case, showing how an ⚫OH scavenger in solution prevents the oxidation of NO2- to NO2 but does not enhance the overall photolysis efficiency of nitrate.

Rational Design of Hydroxylated Thiazole Orange Photocages for Green Light-Triggered DNA Recombination.

The precise control of DNA recombination enables the cell- or time-dependent regulation of gene expression in studies of gene function. Caged estrogen receptor ligands combined with a Cre-ERT2/loxP system are useful tools for light-triggered DNA recombination. However, the photolysis of most caged compounds requires ultraviolet or blue light, which is toxic and displays low tissue penetration. Although a cyanine-based photo-responsive protecting group (PPG) can release estrogen receptor ligands with longer-wavelength light, its low photolytic efficiency requires long illumination times. We developed a caged estrogen receptor ligand with improved green light-responsive PPGs. The rational modification of Hydroxylated Thiazole Orange (HTO) photocages using electron-donating groups (EDGs), such as dimethoxy (DiMeO)-substituted HTO, resulted in high photolytic efficiency (up to ϵΦ ≈320 M-1 cm-1 ). Theoretical calculations demonstrated that the enhanced photolytic efficiencies were derived from the increased intramolecular charge transfer by EDGs upon excitation. The efficient uncaging of estrogen receptor ligands enabled the control of gene recombination in a ligand-dependent Cre-ERT2/loxP system in live cells.

Photochemically Controlled Release of the Glucose Transporter 1 Inhibitor for Glucose Deprivation Responses and Cancer Suppression Research.

Cancer cells need a greater supply of glucose mainly due to their aerobic glycolysis, known as the Warburg effect. Glucose transport by glucose transporter 1 (GLUT1) is the rate-limiting step for glucose uptake, making it a potential cancer therapeutic target. However, GLUT1 is widely expressed and performs crucial functions in a variety of cells, and its indiscriminate inhibition will cause serious side effects. In this study, we designed and synthesized a photocaged GLUT1 inhibitor WZB117-PPG to suppress the growth of cancer cells in a spatiotemporally controllable manner. WZB117-PPG exhibited remarkable photolysis efficiency and substantial cytotoxicity toward cancer cells under visible light illumination with minimal side effects, ensuring its safety as a potential cancer therapy. Furthermore, our quantitative proteomics data delineated a comprehensive portrait of responses in cancer cells under glucose deprivation, underlining the mechanism of cell death via necrosis rather than apoptosis. We reason that our study provides a potentially reliable cancer treatment strategy and can be used as a spatiotemporally controllable trigger for studying nutrient deprivation-related stress responses.

Photo-electrocatalytic degradation of remdesivir from aqueous solutions using Ni-doped ZnO nanocomposite: Kinetic, degradation pathway, toxicity reduction and reusability

Currently, there has been increasing interest in developing active photocatalysts for the treatment of wastewaters. In this study, Nickel (Ni)-doped Zinc oxide on a fluorine tin oxide (ZnO/FTO) was synthesized and utilized as an electrocatalyst for efficient degradation and mineralization of remdesivir (REMD). Ni-ZnO/FTO electrode was characterized using XRD, SEM, EDX, LSV, and DRS analyses. The influence of operational parameters on the degradation efficiency procedure was explored in a batch photo-reactor and their optimum values were selected. At optimized conditions (e.g. initial REMD concentration = 1 mg/L, electrolyte concentration = 0.1 g/L, current intensity = 0.03 A, and pH = 7), within 2 h under UV-A, the removal efficiency of initial REMD concentration was 92 %, whereas TOC and COD removal efficiency were found as 80.1 % and 69.5 %, respectively. The assessment of the degradation rate within 2 h indicates that REMD degradation obeyed first order kinetic model. Additionally, in the comparison of degradation and mineralization efficiency of electrolysis, photolysis and photocatalytic and photoelectrocatalysis (PECP) processes for REMD removal, PECP gave the highest efficiency. The toxicity evaluations showed that the toxicity of solutions treated by the proposed PEC process significantly decreased in comparison with untreated controls. Based on reusability investigations, Ni-ZnO/FTO can be reused for at least five repetitive times with suitable efficiency. Moreover, by taking into account all results, it was concluded that the affordability, high potentiality, and well regenerability of Ni-ZnO/FTO make it an attractive electrocatalyst in terms of drug-containing wastewater treatment.

Elucidating the performance of UV-based photochemical processes for the removal of trace organic contaminants: Degradation and toxicity evaluation

In this study, the performance of standalone ultraviolet (UV) photolysis and UV-based advanced oxidation processes (AOPs), namely, UV/hydrogen peroxide, UV/chlorine, UV/persulphate, and UV/permonosulphate, were investigated for the degradation of 31 trace organic contaminants (TrOCs). Under the tested conditions, standalone UV photolysis did not achieve effective removal of TrOCs. To improve the degradation efficiency of UV photolysis, four different oxidants were added individually to the test solution. The effect of these oxidants in the absence of UV irradiation was also explored and only chlorine showed promising degradation of some contaminants. During the chlorination of 31 investigated TrOCs, only six demonstrated greater than 50% degradation. The combined UV-based AOPs demonstrated much improved degradation (ranging from 65 to 100%) depending on TrOC-structure and oxidant concentration. The UV/hydrogen peroxide process showed similar degradation of TrOCs, irrespective of the functional groups (i.e., electron withdrawing groups, EWGs and electron donating groups, EDGs) present in their structures. Conversely, the UV/sulphate and UV/chlorine based processes achieved better degradation of the TrOCs with EDGs in their structures. TrOCs degradation improved up to 40% when oxidants concentrations were increased from 0.1 to 1 mM, and further increasing the concentration to 2 mM did not improve degradation. Toxicity evaluation using bioluminescence test (BLT assay) demonstrated that except for UV/hydrogen peroxide, all UV-based AOPs increased the toxicity of the treated effluent, indicating generation of toxic by-products. This study elucidates the performance of four different UV-based AOPs for the removal of commonly detected diverse TrOCs for the first time.

Molecular understanding on ultraviolet photolytic degradation of cyano liquid crystal monomers

Cyano liquid crystal monomers (LCMs) are proposed as emerging chemical pollutants with persistent, bioaccumulative, and toxic properties. Herein, five cyano LCMs, including 4-cyano-4′-ethylbiphenyl (2CB), 4-Butyl-4′-cyanobiphenyl (4CB), 4-cyano-4′-ethoxybiphenyl (2OCB), 4-(trans-4-Ethylcyclohexyl)benzonitrile (2CHB) and 4-(trans-4-Vinylcyclohexyl)benzonitrile (2eCHB), were selected to investigate the reaction kinetics and excited state characteristic variations with their molecular structures by ultraviolet (UV) photolysis. Theoretical calculations reveal that the benzene ring, ethoxy and double bond can deeply alter the electron distribution of cyano LCMs. This will affect the exciton separation ability, excitation properties and active sites to electrophilic attack, causing the distinction in photolysis efficiency. Due to the effective charge separation during local excitation (LE) process and the property of being most susceptible to electrophilic attack by 1O2 and O2•−, 2eCHB with double bond exhibits the largest degradation rate. Conversely, the weakest exciton separation of 2OCB with ethoxy during charge transfer (CT) process limits its subsequent sensitized photolysis process. The molecular orbital and fragment contributions to holes and electrons further deepen the understanding of the excited states charge transfer. This study confirmed that the intrinsic molecular structure, chemical nature and existing sites directly defined the excitation and decomposition activity in the UV photolysis of cyano LCMs.

Mechanistic analysis of the photolytic decomposition of solid-state S-nitroso-N-acetylpenicillamine

S-Nitroso-N-acetylpenicillamine (SNAP) is among the most common nitric oxide (NO)-donor molecules and its solid-state photolytic decomposition has potential for inhaled nitric oxide (iNO) therapy. The photochemical NO release kinetics and mechanism were investigated by exposing solid-state SNAP to a narrow-band LED as a function of nominal wavelength and intensity of incident light. The photolytic efficiency, decomposition products, and the photolytic pathways of the SNAP were examined. The maximum light penetration depth through the solid layer of SNAP was determined by an optical microscope and found to be within 100–200 μm, depending on the wavelength of light. The photolysis of solid-state SNAP to generate NO along with the stable thiyl (RS·) radical was confirmed using Electron Spin Resonance (ESR) spectroscopy. The fate of the RS· radical in the solid phase was studied both in the presence and absence of O2 using NMR, IR, ESR, and UPLC-MS. The changes in the morphology of SNAP due to its photolysis were examined using PXRD and SEM. The stable thiyl radical formed from the photolysis of solid SNAP was found to be reactive with another adjacent thiyl radical to form a disulfide (RSSR) or with oxygen to form various sulfonyl and sulfonyl peroxyl radicals {RS(O)xO·, x = 0 to 7}. However, the thiyl radical did not recombine with NO to reform the SNAP. From the PXRD data, it was found that the SNAP loses its crystallinity by generating the NO after photolysis. The initial release of NO during photolysis was increased with increased intensity of light, whereas the maximum light penetration depth was unaffected by light intensity. The knowledge gained about the photochemical reactions of SNAP may provide important insight in designing portable photoinduced NO-releasing devices for iNO therapy.

Factors Influencing the Formation of Nitrous Acid from Photolysis of Particulate Nitrate.

Enhanced photolysis of particulate nitrate (pNO3) to form photolabile species, such as gas-phase nitrous acid (HONO), has been proposed as a potential mechanism to recycle nitrogen oxides (NOx) in the remote boundary layer ("renoxification"). This article presents a series of laboratory experiments aimed at investigating the parameters that control the photolysis of pNO3 and the efficiency of HONO production. Filters on which artificial or ambient particles had been sampled were exposed to the light of a solar simulator, and the formation of HONO was monitored under controlled laboratory conditions. The results indicate that the photolysis of pNO3 is enhanced, compared to the photolysis of gas-phase HNO3, at low pNO3 levels, with the enhancement factor reducing at higher pNO3 levels. The presence of cations (Na+) and halides (Cl-) and photosensitive organic compounds (imidazole) also enhance pNO3 photolysis, but other organic compounds such as oxalate and succinic acid have the opposite effect. The precise role of humidity in pNO3 photolysis remains unclear. While the efficiency of photolysis is enhanced in deliquescent particles compared to dry particles, some of the experimental results suggest that this may not be the case for supersaturated particles. These experiments suggest that both the composition and the humidity of particles control the enhancement of particulate nitrate photolysis, potentially explaining the variability in results among previous laboratory and field studies. HONO observations in the remote marine boundary layer can be explained by a simple box-model that includes the photolysis of pNO3, in line with the results presented here, although more experimental work is needed in order to derive a comprehensive parametrization of this process.

Sanger's reagent as a new general phototrigger for organelle imaging

Photoactivatable subcellular organelles imaging offers the desirable spatiotemporal resolution in studying the complex biological processes. Developing proper and simple photoremovable protecting groups (PPGs) is the key for constructing such imaging probes. In this study, we designed and synthesized three Sanger's reagent caged fluorescent probes for specific photoactivated organelle imaging. We showed the photoactivated fluorescence recovery of the probes. The photolysis mechanism was verified by mass spectra (MS) analysis, and the highly efficient photolysis process was monitored by high performance liquid chromatography (HPLC). The probes successfully imaged their respective targeted organelle, including mitochondria, lysosomes, and endoplasmic reticulum (ER), in a photoactivated manner, and exhibited high co-localization coefficients when compared to commercially available probes. Given the high reactivity and efficient photodissociation capability of Sanger's reagent with amino groups, our examples demonstrate the potential of Sanger's reagent as a novel general PPG for constructing photoactivatable fluorescent probes.

Stabilization of Carbocation Intermediate by Cucurbit[7]uril Enables High Photolysis Efficiency.

A cucurbit[7]uril-based host-guest strategy is employed to enhance the efficiency of photolysis reactions that release caged molecules from photoremovable protecting groups. The photolysis of benzyl acetate follows a heterolytic bond cleavage mechanism, thereby leading to the formation of a contact ion pair as the key reactive intermediate. The Gibbs free energy of the contact ion pair is lowered by 3.06 kcal/mol through the stabilization of cucurbit[7]uril, as revealed by DFT calculations, which results in a 40-fold increase in the quantum yield of the photolysis reaction. This methodology is also applicable to the chloride leaving group and the diphenyl photoremovable protecting group. We anticipate that this research presents a novel strategy to improve reactions involving active cationics, thereby enriching the field of supramolecular catalysis.

Synthesis and characterization of 8-aminoquinoline photocages for biological applications

Inspired by the 8-dimethylaminoquinoline (8-DMAQ) caging chromophore, photocleavable 8-aminoquinoline derivatives were prepared with the aim of furnishing a robust synthetic pathway for novel cage scaffolds. The four-step versatile process allows a facile introduction of various amino-substituents and its overall yield is feasible for scale-up. The novel photocages showed high photolysis efficiency and low fluorescence, comparable to literature reference compounds (as 8-DMAQ-OAc, BHQ-OAc and CyHQ-OAc), demonstrating the utility of the probes for uncaging applications. Several derivatives allow further functionalizations on the side chain, therefore could serve as building blocks for the design of more complex photoresponsive systems.

Mechanisms of ZnO Nanoparticles Enhancing Phototransformation of Biologically Derived Organic Phosphorus in Aquatic Environments.

Zinc oxide nanoparticles (ZnO NPs), as the highly efficient photocatalysts, could enhance the transformation of biogenic organic phosphorus (OP) to orthophosphate (PO43-) by photodegradation, accelerating eutrophication. Conversely, orthophosphate can also transform ZnO NPs and thus potentially alter their catalytic and chemical properties. Here, we investigated the transformation mechanisms of three biogenic OP compounds and ZnO NPs under ultraviolet light (UV) illumination: inositol phosphates (IHPs), nucleic acids (DNA), and aminoethylphosphonic acid (AEP). The physicochemical characteristics of the resulting products were systematically characterized. Results show that ZnO NPs accelerated the transformation of IHPs, DNA, and AEP to inorganic phosphorus with the direct photolysis efficiencies of 98.14, 87.68, and 51.76%, respectively. The main component of the precipitates remained ZnO NPs, and Zn3(PO4)2 was identified. Zinc phytate was determined in the ZnO NP-IHP system. 31P NMR and FTIR further confirmed that the aquatic phase contained orthophosphate. Photoproduced hydroxyl (·OH) and superoxide (·O2-) were proved to play a dominant role in the OP photomineralization. Furthermore, ZnO NPs significantly enhanced the intensity of ·OH and ·O2- compared to the OP and Zn2+ solution alone. This work explored the light-induced mineralization processes of OP with ZnO NPs indicating that nanophotocatalysts may play a positive role in transformation of OP species in aquatic environments to further contribute to eutrophication.

Synthesis and Characterization of CeO2/Ag3PO4 p-n Heterojunction Photocatalyst: Its Photocatalytic Activity for the Degradation of Alizarin Yellow Dye

Novel single and binary photocatalysts were synthesized by coprecipitation method. The crystal structure, surface area, morphology, bandgap energy, functional groups, and optical properties were characterized using XRD, BET, SEM-EDX, UV/vis, FTIR, and PL instruments, respectively. Aqueous solutions of the model contaminant alizarin yellow (AY) dye and real wastewater sample solutions were used to evaluate the photocatalytic activity of single and binary nanocomposite. We found that the photocatalytic activity of CeO2/Ag3PO4 binary nanocomposite is higher than that of their individual counterparts. We investigated the effects of operating parameters such as pH, initial dye concentration, and photocatalytic loading on AY dye degradation. Under optimal conditions, the binary system showed an efficiency of 96.99%. The binary photocatalyst showed relatively higher AY photolysis efficiencies than actual wastewater, about 96.56% and 57.76%, respectively. The actions of various scavengers suggest that ·O2 and ·OH scavengers play an important role in AY decomposition. When the reusability of the photocatalyst was tested, only a reduction of about 20% was observed after four consecutive runs. The degradation of AY follows pseudo-first-order kinetics for newly synthesized nanocomposite. This result indicates that the binary nanocomposite can serve as an excellent medium for electron transport.

Recycling Microplastics to Fabricate Anodes for Lithium-Ion Batteries: From Removal of Environmental Troubles via Electrocoagulation to Useful Resources.

Electrocoagulation is an evolving technology for the abatement of a broad range of pollutants in wastewater owing to its flexibility, easy setup, and eco-friendly nature. Here, environment-friendly strategies for the separation, retreatment, and utilization of microplastics via electrocoagulation are investigated. The findings show that the flocs generated by forming Fe3 O4 on the surface of polyethylene (PE) particles are easily separated using a magnetic force with high efficiency of 98.4%. In the photodegradation of the obtained flocs, it is confirmed that Fe3 O4 shall be removed for the efficient generation of free radicals, leading to the highly efficient photolysis of PE. The removed Fe3 O4 can be recycled into iron-oxalate compounds, which can be used in battery applications. In addition, it is suggested that heat treatment of Fe3 O4 -PE flocs in an Ar atmosphere leads to forming Fe3 O4 core-carbon shell nanoparticles, which show excellent performance as anodes in lithium-ion batteries. The proposed composite exhibits an excellent capacity of 1123 mAh g-1 at the current density of 0.5 A g-1 after 600 cycles with a negative fading phenomenon. This study offers insight into a new paradigm of recyclable processes, from environmental issues such as microplastics to using energy materials.

Visible-light activatable coumarin-based phototriggers for fluorescence imaging with ultra-high photolysis efficiency.

Photoactivated fluorophores (PAFs) are powerful imaging tools for observing subcellular structures and tracking dynamic biological processes. However, photoremovable protecting groups (PPGs) widely used to construct PAFs suffer from the drawbacks of short-wavelength excitation and/or low photolysis efficiency. Herein, a class of coumarin-based PPGs with electron-rich thiophene derived substitutions at the C3-position of a coumarin scaffold were prepared. The modification not only leads to the redshift of the absorption band to the blue light region (400-500 nm), but also the increases of uncaging quantum yield (Φu) as well as molar extinction coefficient (εmax), thus enhancing the photolysis efficiency (Φu × εmax) up to 34.2 × 103 M-1 cm-1. The exceptionally high photolysis efficiency enables efficient photolysis in blue light as weak as 2 mW cm-2 or in blue light from a Luminol chemiluminescence system. Based on the excellent photolysis properties, the PAF constructed by the new PPG exhibits fast photoactivation and a low background signal, and the resulting fluorescence images display a signal-to-noise ratio greater than 780. It is anticipated that the superior photolysis performance makes the PPGs a novel platform for the construction of photo responsive systems in a variety of applications.

Photocatalytic Activity and Wettability Properties of ZnO/Sawdust/Epoxy Composites

In this work, zinc oxide nanoparticles (ZnONPs) and sawdust/epoxy composite (20:80) were mixed using a simple molding method with different ZnONPs concentrations of (0.1, 0.3, 0.5, 0.7, and 1.0 %). The samples of the nanocomposites were characterized by the Scanning Electron Microscopy (SEM) technique to demonstrate the homogeneity of the prepared ZnONPs/nanocomposites. The photocatalytic activity of the samples was examined using the methylene blue (MB) dye as a pollutant solution, through evaluation of the efficiency of the prepared compound in the treatment of organic pollutants under illumination by sunlight. The photocatalytic results showed that after 240 minutes of exposure to sunlight, the sample prepared using (0.5 vol.% of ZnONPs) appeared to rapid degradation of MB dye, with photolysis efficiency of 89% and 71% for dye concentrations 5 and 10 ppm, respectively. Wettability results confirmed that the water contact angles of samples (WCAs) were affected by the concentration of ZnONPs.

Photolysis by UVA-Visible Light of TNT in Ethanolic, Aqueous-Ethanolic, and Aqueous Solutions According to Electrospray and Aerodynamic Thermal Breakup Droplet Ionization Mass Spectrometry.

The mechanism of photolytic degradation of 2-4-6-trinitrotoluene (TNT) by UVA-visible light (>320 nm) in ethanolic, aqueous-ethanolic, and aqueous solutions was investigated by electrospray and aerodynamic thermal breakup droplet ionization mass-spectrometric analyses. For the photolysis, a DRK-120 mercury-quartz lamp was used. Products of the photolysis reaction were compared with known products of TNT transformation in the environment. Because the photochemistry of some compounds in alcohols (in contrast to aqueous solutions) features a transfer of electrons from the solvent to the light-excited compound, we believe that the efficiency of photolysis (polymerization) of TNT in ethanol and aqueous-ethanolic solutions is based on this mechanism.

Reductive removal of As(V) and As(III) from aqueous solution by the UV/sulfite process: Recovery of elemental arsenic

The removal of arsenic (As(V) and As(III)) from contaminated water has attracted great attention. However, the generation of arsenic-containing hazardous waste by traditional methods has become an inevitable environmental problem. Herein, a UV/sulfite advanced reduction method was proposed to remove As(V) and As(III) from aqueous solution in the form of valuable elemental arsenic (As(0)), thus avoiding the generation of arsenic-containing hazardous waste. The results showed that greater than 99.9% of As(V) and As(III) were reduced to the high purity As(0) (> 99.5 wt%) with the residual arsenic concentration below 10 μg L−1. The hydrated electrons (eaq−), H• and SO3•− radicals are generated by the UV/sulfite process, of which eaq− and H• serve as reductants of As(V) and As(III) while the SO3•− radicals inhibit arsenic reduction by oxidizing arsenic. The effective quantum efficiency (Φ) for the formation of As(0) in the As(V) and As(III) removal process is approximately 0.0078 and 0.0055 mol/Einstein, respectively. The reduction of arsenic is favorable under alkaline conditions (pH > 9.0) due to the higher photolysis efficiency of SO32− than HSO3− (pKa = 7.2) and higher stability of eaq−/H• under alkaline conditions. The presence of dissolved oxygen (O2), NO2−, NO3−, CO32−, PO43− and humic acid (HA) inhibited arsenic reduction through light blocking or eaq−/H• scavenging effects while Cl−, SO42−, Ca2+ and Mg2+ had negligible effects on arsenic reduction. The proposed method can effectively remove and recover arsenic from contaminated water at a low cost, demonstrating feasibility for practical application. This study provides a novel technology for the reductive removal and recovery of arsenic from contaminated water.