Photographic Waste Research Articles

Epoxy/Graphite Composite Electrode Modified with Recycled Silver Nanoparticles: An Eco-Friendly Strategy to Improve Lead Detection

In this work, silver nanoparticles (AgNPs) obtained from photographic waste were synthesized and electrodeposited via cyclic voltammetry using epoxy-graphite composite as an electrochemical substrate. Both electrodes, unmodified (Epoxy/C) and modified (Epoxy/C/AgNPs), were characterized electrochemically by electrochemical impedance spectroscopy (EIS), charge transfer constant (K0 ), and electroactive area. The modified electrode provided lower charge transfer resistance (275 Ω), more kinetically favored electron transfer (K0 = 1.15 × 10-3 cm s-1), and a 1.7- fold increase in the active area compared to the unmodified electrode. Additional characterizations by scanning electron microscopy (SEM) and Raman spectroscopy confirmed the presence of AgNPs structures on the carbonaceous surface. As a proof of concept, Pb2+ was used as a model analyte, and a square wave anodic stripping voltammetry (SWASV) method was developed to evaluate the analytical performance of both electrodes. A wider linear range (4.0 to 40.0 µg L-1), the appropriate limit of detection (1.2 µg L-1), and a 6-fold increase in sensitivity were found using the modified electrode, suggesting that the AgNPs significantly contributed to the performance of the electrode. The proposed method was applied to three real water samples, where the Pb2+ levels varied from 11.3 to 19.5 µg L-1. The proposed protocol (reuse of silver waste) has proven to be a powerful tool for improving the detection of Pb2+, which can be helpful for other electrochemical sensing applications in locations with minimal infrastructure.

Study of Methylene Blue Adsorption with Silver Chloride Coagulants from Photographic Film Waste

Methylene blue is a dye that is widely used in industry. These dyes are hazardous and can pose a health risk if discharged directly into the environment. On the other hand, photographic waste containing Ag metal can be used as an AgCl coagulant. This study aims to determine the effectiveness of AgCl coagulant in the adsorption of methylene blue dye. Silver chloride was synthesized from photographic waste using the coagulation precipitation method. The results of the analysis showed that the AgCl coagulant was able to take 88.2% methylene blue dye at neutral pH 7 for 15 min with a stirring speed of 300 rpm for 10 mg/L methylene blue sample. The adsorption capacity of AgCl was 10.9 mg. g -1 and the adsorption kinetics model was pseudo-order 1 with an R 2 value of 0.9318. Keywords: AgCl, coagulant, methylene blue DOI: 10.7176/JEES/12-4-06 Publication date: April 30 th 2022

Fabrication of medicinal transdermal patch impregnated with silver nanoparticles synthesized from biomedical photographic wastes

article: Fabrication of medicinal transdermal patch impregnated with silver nanoparticles synthesized from biomedical photographic wastes - Minerva Biotechnology and Biomolecular Research 2021 December;33(4):219-25 - Minerva Medica - Journals

Catalytic Reclamation of Silver Present in Photographic Waste Using Magnetically Separable TiO2@CuFe2O4 Nanocomposites and Thereof Its Use in Antibacterial Activity.

In the present investigation, the silver present in photographic waste is reclaimed catalytically using magnetically separable TiO2@CuFe2O4 nanocomposites (NCs), and further, the recovered silver nanoparticles [Ag(0) NPs] are tested against the representative bacteria for the antibacterial activity. Initially, a series of the different composites between TiO2 nanoparticles and CuFe2O4 nanoparticles are synthesized by a sol–gel “ex situ” method to enhance the catalytic activity of bare nanomaterials toward the visible region of the electromagnetic spectrum. X-ray diffraction reveals the presence of characteristic patterns for the tetragonal structure in the bare materials or TiO2@CuFe2O4 NCs; however, the dominance in the phase as well as intensity of the respective XRD reflections in the NCs is observed according to the content of TiO2 or CuFe2O4 in the NCs. Field-emission electron microscopic images show the uniform spherical particles for the representative TiO2@CuFe2O4 NCs, which is also confirmed through the HRTEM images. The magnetically separable behavior of the representative TiO2@CuFe2O4 NCs is confirmed through the VSM measurements, which also shows the superparamagnetic properties due to the S-shaped nature of the hysteresis loop. Thereafter, a photoconversion reaction of Ag(I) ions to Ag(0) NPs as a model reaction is carried out using the different TiO2@CuFe2O4 NCs under visible light irradiation, and hence, the higher catalytic recovery of Ag(0) NPs is observed for a composite containing 10 wt % TiO2 and 90 wt % CuFe2O4 than that of other NCs or the bare one alone. The optimized protocol of the model reaction is adopted for reclaiming Ag(0) NPs from photographic waste. The progress of the catalytic reclamation reaction is monitored using UV–visible, and then sizes of the recovered Ag(0) NPs are confirmed through the HRTEM images. Thereafter, the recovered Ag(0) NPs are tested for complete photoinactivation of Escherichia coli bacteria within 120 min.

Emulsion Liquid Membrane Extraction of Silver from Photographic Waste using Tetramethylthiuram Disulfide (TMTDS) as a Mobile Carrier

The recovery of precious metals such as silver from photographic wastes is required in order to save raw materials and to protect the environment from dispersed compound, especially heavy metals. For that matter, several technologies have been used such as precipitation, electrolytic, and ion exchange processes which offer some advantages as well as drawbacks over others. Recently, emulsion liquid membrane extraction has been recognized to be a potential process for industrial wastes treatment and recovery of heavy metals. This process has the ability to selectively separate and rapidly concentrate metals through its very thin layer liquid membrane which has a large interfacial area. An attempt was made to recover silver from liquid photographic wastes using tetramethylthiuram disulfide as a mobile carrier. The important variables affecting the emulsion liquid membrane (ELM) process including residence time, surfactant concentration, carrier concentration, level of agitation and phase ratio between emulsion and feed phase were investigated. The results showed that tetramethylthiuram disulfide is selective towards silver (>80%) compared to other metals in the photographic waste. The highest silver extraction is obtained using 0.05 M tetramethylthiuram disulfide, 3% (w/v) Span 80, 300 rpm stirring speed, 1.0 M thiourea in 0.1 M HCl stripping agent, 1:3 of treat ratio, and toluene as the diluent.

Selective Transport of Silver(I) Cation Across a Bulk Liquid Membrane Containing Bis-β-enamino Ester as Ion Carrier

Facilitated transport of silver(I) cation across a bulk liquid membrane by two synthesized ligands, bis-β-enamino ester (BBEE) and bis(benzoic acid) trioxaheptane (BBAT), as carriers dissolved in dichloromethane has been investigated. BBEE was used as a specific ion carrier for the transport of silver(I) ion. The influence of experimental parameters affecting the transport efficiency of silver(I) ion have been studied. In the presence of thiosulfate as a suitable metal ion acceptor in the receiving phase and picrate ion as ion pairing agent in the source phase, the amount of silver(I) ion transported across the liquid membrane after 120 min was found to be 97%. Tolerance to the presence of different ions was investigated and it was found that silver(I) cation transport was not affected even in the presence of 10-fold concentration of these metal cations in solution. This system was applied for the recovery of silver(I) cation from silver plating and photographic waste solution.

Silver Adsorption Enhancement from Aqueous and Photographic Waste Solutions by Mercerized Coconut Fiber

The mercerized coconut fiber (CF-NaOH) was prepared by treating the pristine coconut fiber (CF-Pure) with NaOH solution. The morphology and chemical composition of CF-Pure changed after mercerization process. The maximum Ag(I) adsorption capacity of the CF-Pure and CF-NaOH was 0.502 and 0.612 mmol/g, in which the equilibrium data fitted to the Freundlich and Langmuir isotherm models, respectively. The Ag(I) adsorption rate also increased by using CF-NaOH and the kinetic data of both CF-Pure and CF-NaOH obeyed the pseudo-second order kinetic model. The enhancement of Ag(I) adsorption selectivity from photographic waste solution was also observed for the CF-NaOH.

Estimation of silver content in some photographic wastes

The concentration of silver in some photographic wastes (photographic solution, stabilizer solution and photographic films) has been determined in this study. Plantain ash solution (PAS) of different concentrations was used as solution for stripping the films and as extractant for the photographic solutions. Products obtained were analysed for silver content. The concentration of silver was measured using UV-visible spectrophotometer at a wavelength of 380nm, path length 1cm using silver nitrate for calibration. Results obtained revealed that plantain ash solution extracted silver from the various wastes in all the concentrations of PAS used. However the silver content was observed to be highest in the photographic film and fixer solution and lowest for stabilizer solution in the particular instance. In all the photographic wastes studied, it was observed that although more products were recovered by using higher concentrations of PAS, higher concentrations of silver ions were obtained when lower concentrations of PAS were used (0.1500 -0.8450M ). Therefore lower concentrations of PAS can be used for leaching of photographic wastes of silver.

Photocatalytic and immobilization characteristics of immobilized ZnO and TiO2 nanopowders

A kind of photocatalytic ZnO nanopowder and two kinds of photocatalytic TiO2 nanopowders were prepared. The ZnO nanopowder was synthesized by the solution combustion method, which was invented by the present authors. One of the TiO2 nanopowders was synthesized by HPPLT (homogeneous precipitation process at low temperature) method in this work. The other TiO2 nanopowder (P-25 TiO2, a popular commercial titania photocatalyst) was purchased. These photocatalytic nanopowders were immobilized by several kinds of binders. The immobilization characteristics were examined by XRD, ultrasonication, and SEM. The photocatalytic characteristics were measured by photocatalytic Ag ion extraction rate. The Ag ions were extracted from real (not artificial) photographic waste fixing solution. The Ag ion extraction rate with the immobilized ZnO nanopowder was more than twice that reported for other immobilized photocatalysts.

EFFECT OF MATRICES ON PERCENT EXTRACTION OF SILVER (II) FROM BLACK/WHITE PRINTING PHOTOGRAPHIC WASTE USING EMULSION LIQUID MEMBRANE TECHNIQUE

Extraction of silver (I) has been studied from black/white printing photographic waste by emulsion liquid membrane technique. Composition emulsion at the membrane phase was cerosene as solvent, sorbitan monooleat (span 80) as surfactant, dimethyldioctadesyl-ammonium bromide as carrier and as internal phase was HNO3. Optimum condition was obtained: ratio of internal phase volume and membrane phase volume was 1:1 : concentration of surfactant was 2% (v/v) : time of making emulsion was 20 second : rate of stiring emulsion was 1100 rpm : rest time emulsion was 3 second : rate of emulsion volume and external phase volume was 1:5 : emulsion contact rate 500 rpm : emulsion contact time was 40 second : concentration of silver thiosulfate as external phase was 100 ppm : pH of external phase was 3 and pH of internal phase was 1. Optimum condition was applied in silver(I) extraction from black/white printing photographic waste. It was obtained 77.33% average which 56.06% silver (I) average of internal phase and 22.66% in the external phase. Effect of matrices ion decreased silver(I) percent extraction from 96,37% average to 77.33% average. Keyword: photographics waste, silver extraction

Preparation of calix[4]arene methylene crosslinked resins with 2-pyridyl pendant group and their adsorption behavior towards silver ion

Three different resins namely 1:5 MC-resin, 1:3 MC-resin and 1:1 MC-resin have been synthesized by methylene crosslinking of 2-pyridylcalix[4]arene. Adsorption behavior of these resins towards the metal ions existing in photographic waste was investigated. The resins show absolute efficiency for adsorption of silver ion with no affinity for other coexisting ions. First two resins form 1:1 complex whereas the third one forms 2:1 complex with silver ion. Maximum loading capacity of silver ion on the present resins was found to be 1.15, 1.29 and 0.69 mol kg−1, respectively. Column chromatographic separation of silver ion in presence of excess of sodium ions was also carried out with 1:5 MC-resin. Selective adsorption of silver ions over excess of sodium ions was achieved.

Intra/Extracellular Biosynthesis of Silver Nanoparticles by an Autochthonous Strain of <I>Proteus mirabilis</I> Isolated fromPhotographic Waste

There is an enormous interest in developing green synthesis procedures for production of nanoparticles by using biomimetic approaches. In our research focus has been given to the development of an efficient and eco-friendly viable process for the synthesis of nanoscale silver particles using Proteus mirabilis PTCC 1710, a bacterial strain that was isolated during a screening program from photographic waste. A significant result of this study is our observation that silver nanoparticles could be induced to synthesis intra and extracellulary. The silver nanoparticles were characterized by means of UV-Vis spectroscopy, transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDS) and atomic absorption spectrometer (AAS). The nanoparticles exhibited maximum absorbance at 400-410 nm in UV-Vis spectroscopy. TEM images showed formation of stable silver nanoparticles of spherical shape with most of the particles in the size range of 10-20 nm. It was found that incubation of bacterial cells in Muller-Hinton broth medium resulted in higher extracellular synthesis of silver nanoparticles, whereas intracellular synthesis of silver nanoparticles effectively increased in tryptic soy broth. The method of extraction of intracellular silver nanoparticles was inexpensive, simple and effective in large scale with no need to complex instruments. The bacteria work as a bionanofactory which continued to grow after synthesis of silver nanoparticles. The silver reduction by this strain is occurred through energy-dependent processes that lead to the high output of this reaction. Hence this new approach of using a non-pathogenic bacterial strain for the successful synthesis of nanosized silvers could be easily scaled up which establishes its commercial viability.

Separation of silver from photographic wastes by emulsion liquid membrane system

Separation of silver from liquid photographic waste containing various ions such as silver, ferum, sodium, and potassium by an emulsion liquid membrane containing Cyanex 302 as a carrier has been carried out. The important parameters governing the extraction behavior of silver have been investigated. These parameters were agitation speed, surfactant concentration, carrier concentration, type of diluents, treat ratio, and acid types in the stripping solution. The process has been conducted in a batch system using a mixer–settler. The results showed that the mobile carrier Cyanex 302 is selective towards silver compared to the other metals in the photographic waste. The highest silver extraction is obtained by using 0.05 M Cyanex 302, 3% (w/v) Span 80, 4.166 Hz (250 rpm) stirring speed, 1.0 M thiourea in 1.0 M H 2SO 4 stripping agent, 1:5 of treat ratio, and kerosene as a diluent.

Di ( n-propyl) thiuram disulfide bonded on silica gel as a new sorbent for separation, preconcentration, and measurement of silver ion from aqueous samples

A new synthesized sorbent, di ( n-propyl) thiuram disulfide bonded on silica gel, was applied for separation and preconcentration of silver ion from aqueous samples. Factors influencing the sorption and desorption of silver ion were investigated. An aqueous solution containing sodium thiosulfate was used as eluent in order to selectively desorb the adsorbed silver ion from the surface of the sorbent. A preconcentration factor of 100 was achieved. The effect of coexisting ions in binary mixtures, containing silver ion and the foreign ion, on percent recovery of silver ion was investigated. Mercury(II) ion showed interfering effect. Separation selectivities for each metal ion of Zn 2+, Cu 2+, Co 2+, Ni 2+, Al 3+, Hg 2+, Pb 2+, Ca 2+, Cr 3+, Mg 2+, and Fe 3+ were measured. The relative standard deviation under optimum conditions was 1.43% ( n = 10). This system was applied for determination of silver ion in photographic waste and lakewater samples.

Precious Metal Extraction from Liquid Photographic Wastes

Waste generating from photographic industry contains metals, which basically need to recover due to either economic reasons or to treat and remove the toxic metals before it can discharge into environment. Extraction of precious metals such as silver from this waste is very attractive. However, selection of the right technique is crucial in order to obtain relatively pure products. Solvent extraction may offer some advantages over other techniques. In solvent extraction process, selection of the right extractant, which offers high selectivity and capacity is important especially when involves extraction of metal from mixed diluted metals solution like photographic wastes. Therefore, different types of extractants were examined in this study in term of their capability and selectivity in extracting metals from photographic waste. It was found that the Cyanex 302, dithizone and tetramethylthiuram disulfide are most promising extractants amongst others in extracting silver. It was found that also more than 90% of silver was extracted using only 0.05M extractant. This result shows that extractants containing sulfur donor atoms have high selectivity towards silver compared to other metals. Stripping of extracted metals from organic-loaded metals solution using various stripping agents such as nitric, hydrochloric and sulphuric acids shows that nitric acid gives a good capability to strip silver from metal loaded tetramethylthiuram disulfide and Cyanex 302. Metal loaded dithizone could not be stripped using these acids. Further study shows that the extent of extraction process depends on, not only on extractant concentration but also on the initial pH of the liquid photographic waste.

Recovery of silver-thiosulphate complexes with chitin

Chitin was able to adsorb anionic silver-thiosulphate complexes at pH 2.2 within 5 min. The particle size affected adsorption capacity. The maximum adsorption capacity of chitin powder and flake was 4.37 and 3.61 mg Ag/g, respectively. A high concentration of thiosulphate had the strongest influence on silver-thiosulphate adsorption, because it could form stable-dissoluble silver complexes. The mechanism of silver adsorption was analysed from the effects of pH, contact time, agitation rate, thiosulphate concentration, adsorption isotherms and elution. Results indicated that the adsorption of silver-thiosulphate had two mechanisms: electrostatic interaction between protonated chitin and the anionic silver, and coordinate covalent bonding between lone pair electrons of nitrogen and/or oxygen and silver. Adsorbed silver was completely eluted by 3.0 M of sodium thiosulphate. The application of chitin for recovery of silver from photographic waste and the treatment of chitin to increase adsorption capacity, require further study.

Wire-coated silver(I) ion-selective electrode based on 2-mercaptobenzothiazole (MBT) ionophore: application to the determination of silver in real samples.

A new wire-coated silver ion-selective electrode with a wider concentration range (10(-7) M - 10(-1) M) was developed using 2-mercaptobenzothiazole (MBT) as a neutral ionophore. An optimum mixture of PVC, ionophore, dioctylphtalate (DOP) as a plasticizer and sodium tetraphenylborate (NaTPB) as an ion-pairing agent was used in preparing the coatings. The effect of various parameters, such as the electrode bed nature, coating composition and solution pH, on the efficiency of the electrode is described. It has been shown that platinum acts as a more suitable bed for electrode preparation, and exhibits a slope of 59.5 +/- 1 mV over the whole range of studied concentrations. The selectivity coefficient of the electrode towards various interfering cations as well as its reproducibility, response time and lifetime of the electrode were estimated. The developed electrode was successfully used for the determination of trace amounts of silver in human hair and photographic waste as real samples and in the potentiometric titration of halides as an indicator electrode.

Degradation of color photographic waste fix solution by anodic oxidation

AbstractBy use of a capillary electrophoretic method for anion analysis the anodic oxidation of thiosulfate, present in color photo bleach‐fix solutions, was investigated. In a specially constructed electrolysis cell with a cation‐exchange membrane separating the electrode chambers and with a carbon flow‐through three‐dimensional anode the two‐stage anodic oxidation of S2O32− anions was realized. In the first stage, S2O32− anions were oxidized to a maximal degree to an intermediate compound – tetrathionate (S4O62−) – then S4O62− anions were oxidized to the sulfate (SO42−), avoiding the decomposition of intermediate compounds and the formation of harmful sulfur compounds.© 2002 Society of Chemical Industry

SILVER-SELECTIVE MEMBRANE ELECTRODES USING 2-MERCAPTOBENZIMIDAZOLE AND 2-MERCAPTOBENZOTHIAZOLE CARRIERS

ABSTRACT Silver ion-selective electrodes based on 2-mercaptobenzimidazole (MBI) and 2-mercaptobenzothiazole (MBT) carriers have been developed. The poly(vinyl chloride) (PVC)-based membranes containing MBI or MBT, plasticizer and sodium tetraphenylborate, as anion excluder and membrane modifier, were directly coated on the surface of graphite electrodes. The electrodes exhibited near-Nernstian slopes of 60.2 and 57.8 mV per decade of Ag+ concentration for MBI and MBT, respectively. Calibration plots were linear over a wide concentration range of 1 × 10−6–1 × 10−2 M Ag+. The electrodes have shown detection limits of 6.3 × 10−7 and 4 × 10−7 M for MBI- and MBT-based electrodes, respectively, and revealed good selectivities over a number of alkali, alkaline earth, transition and heavy metal ions. The electrodes have response times between 10–20 s and can be used for at least two months without a considerable divergence in their potential responses Application of the electrodes for potentiometric titrations and determination of Ag+ ion concentration in photographic waste solutions are reported.

Amperometric determination of thiosulfate at a surface-renewable nickel(II) hexacyanoferrate-modified carbon ceramic electrode

Graphite powder-supported nickel(II) hexacyanoferrate (NiHCF) was prepared by the in situ chemical deposition method and then dispersed into methyltrimethoxysilane-derived gels to form a conductive composite. The composite was used as electrode material to construct a surface-renewable three-dimensional NiHCF-modified carbon ceramic electrode. Electrochemical behavior of the chemically modified electrode was well characterized using cyclic and square-wave voltammetry. The electrode presented a good electrocatalytic activity toward the oxidization of thiosulfate and thus was used as an amperometric sensor for thiosulfate in the photographic waste effluent. In addition, the electrode exhibited a distinct advantage of surface-renewal by simple mechanical polishing, as well as simple preparation, good chemical and mechanical stability.