Determination Of Pb(II), Cu(II) And Ni(II) In Water By Direct Measurement Using Uv/Vis Spectrophotometer

Logam berat merupakan unsur logam dengan ketumpatan yang tinggi dan kebanyakannya bersifat toksik pada kepekatan yang rendah. Selain itu, kepekatan logam berat dalam organisma akan semakin meningkat dengan masa disebabkan oleh sifat bioakumulasi daripada logam berat dan tidak dapat diuraikan. Teknik terkini untuk menentukan logam berat dalam air adalah melalui AAS, IC, ICP-AES, ICPMS, XRF dan elektrokimia. Teknik-teknik ini dapat memberi ketepatan yang tinggi dalam pengukuran tetapi memerlukan kos penyelenggaraan yang tinggi dan prosedur penyediaan yang rumit. Dalam penyelidikan ini, analisis kuantitatif terhadap ion Pb2+, Cu2+ dan Ni2+ dalam larutan akueus telah berjaya dijalankan dengan menggunakan UV/VIS spektroskopi tanpa reagen kimia tambahan. Penyelidikan bermula dengan mengenalpasti panjang gelombang yang berkesan untuk penyerapan dan kemudiannya disahkan dengan bilangan sampel yang banyak. Daripada penyelidikan ini, panjang gelombang berkesan untuk penyerapan di dalam julat UV bagi Pb2+ dan Cu2+ adalah daripada 200 nm hingga 230 nm dan Cu2+ dan Ni2+ daripada 600 nm hingga 800 nm. Heavy metal are metallic element with relatively high density and mostly toxic at low concentration. Heavy metal does not degrade and tends to bioaccumulate in organism over time. Current technique to determine heavy metals in water mostly via AAS, IC, ICP-AES, ICP-MS, XRF and electrochemical method,these techniques provide high precision in measurement but required high maintenance cost and complicated preparation. In this research, quantitative analysis of Pb2+, Cu2+ and Ni2+ ions in aqueous solution was carried out successfully using UV/VIS spectroscopy without additional chemical reagent. The research begins with identifying the effective absorption wavelength and was later verified using large amount of samples. From this research, the effective wavelength within UV range for Pb2+ and Cu2+ is roughly from 200 nm to 230 nm and both the Cu2+ and Ni2+ have absorbance from wavelength 600 nm to 800 nm

Color Removal from Combined Dye and Fruit Nectar Wastewater Using Adsorption and Microfiltration

Pollution of the waterways is a great challenge of the 21st century. Textile effluents contain compounds which have the capacity to cause more harm when ingested. There are many dye removal technologies like coagulation, photo oxidation which help to remove color from dye wastewater. The use of adsorption to remove color from dye wastewater has been used for many centuries. Activated carbon can efficiently remove color from dye wastewater but it is very expensive and so different researches have been conducted to get the adsorption capacity of different forms of adsorbents. These adsorbents can be gotten from agricultural waste, biomass, and industrial waste and even household materials like paper. In this research, agricultural adsorbents like orange peel, banana peel and onion peel are being used as adsorbents to treat dyes like Acid red 88, Direct blue 15 and Rhodamine 6G. The amount of adsorbent dose and dye concentration is being varied to know at what dye concentration or adsorbent dose effectively removes color from dye wastewater. In this study, the treatment of a binary mixture of dye wastewater with fruit drink of different concentrations, low (10ppm), medium (50ppm) and high (100ppm). The dye waste water was prepared in the laboratory while the fruit drink was bought from a local grocery store. Color removal efficiency was investigated for the three adsorbents; orange peel, banana peel, onion peel. Transmittance and Absorbance values were used to determine the removal efficiency of the adsorption proces

Effective Adsorption of Hexavalent Chromium and Divalent Nickel Ions from Water through Polyaniline, Iron Oxide, and Their Composites

Water pollution caused by industrial wastes containing heavy metals and dyes is a major environmental problem. This study reports on the synthesis, characterization, and utilizations of Polyaniline (PANI) and its composites with Fe3O4 for the removal of hexavalent chromium Cr(VI) and divalent nickel Ni(II) ions from water. The adsorption data were fitted in Freudlich, Langmuir, Tempkin, Dubbanin–Ruddishkawich (D–R), and Elovich adsorption isotherms. The Freundlich isotherm fits more closely to the adsorption data with R2 values of 0.9472, 0.9890, and 0.9684 for adsorption of Cr(VI) on Fe3O4, PANI, and PANI/Fe3O4 composites, respectively, while for adsorption of Ni(II) these values were 0.9366, 0.9232, and 0.9307 respectively. The effects of solution pH, initial concentration, contact time, ionic strength, and adsorbent dosage on adsorption behavior were investigated. The adsorption ability of composites was compared with pristine PANI and Fe3O4 particles. Activation energy and other thermodynamic properties such as changes in enthalpy, entropy, and Gibbs free energy indicated spontaneous and exothermic adsorption

Frequency of Use Minute Concentrations of Cadmium in Aqueous Solution by Near Infrared Spectroscopy and Aquaphotomics

Cadmium (Cd) is a common industrial pollutant with long biological half-life, which makes it a cumulative toxicant. Near-infrared spectroscopy has been successfully used for quick and accurate assessment of Cd content in agricultural materials, but the development of a quick detection method for ground and drinking water samples is of equal importance for pollution monitoring. Metals have no absorbance in the NIR spectral range, thus the methods developed so far have focused on detection of metal-organic complexes. This study uses Aquaphotomics to measure Cd in aqueous solutions by analyzing the changes in water spectra that occur due to water-metal interaction. Measurements were performed with Cd (II) in 0.1 M HNO3, in the 680-1090 nm (water second and third overtones) and 1110-1800 nm (water first overtone) spectral regions, and were subjected to partial least-square regression analysis. A concentration of Cd from 1 mg L-1 to 10 mg L-1 could be predicted by this model with average prediction correlation coefficient of 0.897. The model was tested by perturbations with temperature and other metal presence in the solution. The regression coefficient showed consistent peaks at 728, 752, 770, 780, 1362, 1430,1444, 1472/1474 and 1484 nm under various perturbations, indicating that these water absorbance changes were due to Cd presence. The residual predictive deviation values (RPD) were greater than 2, indicating that the model is appropriate for practical us

Treatment of Combined Acid Black 48 and Coffee Wastewater by Low-Cost Adsorbents

© 2020, Kaunas University of Technology. All rights reserved. Removal of synthetic dyes from wastewater is essential both from the environmental and human health point of view. A small concentration of synthetic dyes can reduce water transparency and consequently influence photosynthesis and alter aquatic ecosystems. Acid black 48 is an Azo dye that falls under the category of synthetic dyes used in the textile industry. With dyes, coffee wastewater has high chemical oxygen demand (COD) that can affect dissolved oxygen (DO) in surface waters. A mixture of wastes in surface waters creates a need to investigate the efficiency of existing treatment methods and optimize them. Adsorption using activated carbon is a conventional method used to remove dyes and heavy metals from wastewater. Industries prefer efficient and economical treatment methods to meet challenging effluent standards regarding COD, BOD, and intensi-ty of color. The adsorption process was optimized using low-cost adsorbents in the current study, including peanut hull and onion peel, to treat a binary mixture of acid black 48 and coffee wastewater. After adsorption, microfiltration was used to remove any suspended solids from the wastewater solution. The performance of combined treatment processes for the color removal of the binary mixture was analyzed and compared using transmittance and absorbance. Treatment efficiency of adsorption using low-cost adsorbents was compared with powdered activated carbon. Apart from absorbance and transmittance, non-purgeable organic carbon (NPOC) values were analyzed to determine organic carbon removal in the combined binary wastewater. Experimental results indicated that Langmuir isotherm was the best fit for a binary mixture with an optimum dosage of 1.2 g using onion peel. The regression coefficient value was 0.82, and the uptake was 58.13 mg of binary mixture per 1 g of onion peel. The effective pH for maximum uptake of acid black 48 using onion peel for adsorption was 5.7. The increasing dosage of low-cost adsorbents adsorption improved in removing binary waste of dyes and coffee waste from wastewater. Adsorption using onion peel improved adsorbent performance up to 1.2 g dosage and steadily decreased beyond that. The adsorption capacity of onion peel was comparatively higher than the peanut hull based on the linear fit

Photoactive Materials: Synthesis, Applications and Technology

This book presents a collection of 13 original research articles that focus on the science of light–matter interaction. This area of science has been led to some the greatest accomplishments of the past 100 years, with the discovery of materials that perform useful operations by collecting light or generating light from an outside stimulus. These materials are at the center of a multitude of technologies that have permeated our daily life; every day we rely on quantum well lasers for telecommunication, organic light emitting diodes for our displays, complementary metal–oxide–semiconductors for our camera detectors, and of course a plethora of new photovoltaic cells that harvest sunlight to satisfy our energy needs. In this book, top-rated researchers present their latest findings in the field of nano-particles, plasmonics, semi-conductors, magneto-optics, and holography

Towards Developing Mid-Infrared Photonics Using Mxenes

Recent research and development in the mid-infrared (IR) wavelength range (2-20 um) for a variety of applications, such as trace gas monitoring, thermal imaging, and free space communications have shown tremendous and fascinating progress. MXenes, which mainly refer to two-dimensional (2D) transition-metal carbides, nitrides, and carbonitrides, have drawn a lot of interest since their first investigation in 2011. MXenes project enormous potential for use in optoelectronics, photonics, catalysis, and energy harvesting fields proven by extensive experimental and theoretical studies over a decade. MXenes offers a novel 2D nano platform for cutting-edge optoelectronics devices due to their interesting mechanical, optical, and electrical capabilities, along with their elemental and chemical composition. We here discuss the key developments of MXene emphasizing the evolution of material synthesis methods over time and the resulting device applications. Photonic and optoelectronic device design and fabrication for mid-IR photonics are demonstrated by integrating MXene materials with various electrical and photonic platforms. Here, we show the potential of using Mxene in photonics for mid-IR applications and a pathway toward achieving next-generation devices for various applications.Comment: 50 Pages, 21 figure

The synthesis, characterization and performance evaluation of polyphelenediamine- and polypyrrole- clay composites for removal of oxo-anionic wastewater contaminants

A thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Faculty of Science, University of the Witwatersrand, 2018Contamination of water bodies by numerous pollutants is a worldwide problem that endangers the environment and health of human beings, animals and aquatic life. Hexavalent chromium (Cr(VI)) for example is used in different metal products and processes which makes it a common environmental contaminant. Because of its high mobility in aqueous phase, and improper storage or unsafe disposal practices, leakage of Cr(VI) into water streams and ground water is a common occurrence. While Cr(III) is an essential micronutrient, Cr(VI), however is highly toxic posing serious health risks. Additionally, phosphorus is a limiting nutrient for the growth of organisms in most ecosystems, but, excessive discharge of phosphate ions in water systems leads to profuse algal growth, and is detrimental to both the environment and the ecosystem. This research focused on the development of suitable functional adsorbents for the removal of Cr(VI) complexes and phosphate ions from wastewater. Poly(para-phenylene)- (PpPD) and polypyrrole-based composites were synthesized through chemical oxidation polymerization, and investigated for Cr(VI) remediation. Poly(phenylenediamine) isomers were synthesized through different chemical oxidation methods for the uptake of phosphate ions in wastewater. Transition metals modified bentonite clay adsorbents were developed to remove phosphate ions in aqueous solution.The adsorbents were characterized using Fourier-transform infrared spectroscopy (FT-IR), X-ray diffractometer (XRD), Brunauer-Emmett-Teller (BET), Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX), Thermogravimetric analyzer (TGA) and X-ray photoelectron spectroscopy (XPS) instruments. Adsorption kinetics and isotherm models were investigated. In the first study of this work (paper I), PpPD and PpPD-clay composite were successfully prepared and applied for Cr(VI) removal and reduction in aqueous solution. Characterization by XRD demonstrated that PpPD molecules intercalated into clay galleries. Additionally, PpPD functional groups dominated in the composite even though the signal bands were smaller than the pristine polymer bands indicating that there was a formation of polymeric structure inside the organoclay interlayer spaces. Batch adsorption studies showed that pH, adsorbent dosage, contact time and Cr(VI) concentration affected the degree of adsorption. The Langmuir maximum adsorption capacity for Cr(VI) was 217.4 mg/g and 185.2 mg/g whereas for total Cr it was 193.3 mg/g and 148.8 mg/g for PpPD and PpPD-organoclay, respectively at an optimum pH of 2. Paper II focused on the chemistry of Cr(VI) adsorption by PpPD and adsorbent regeneration. The adsorption mechanism on the material surface was revealed by XPS and FT-IR. Cr(VI) was reduced to Cr(III) which complexed onto the adsorbent surface at the studied pH of 2 and 8. Desorption of the adsorbed Cr was conducted using NaOH (0.05 M) and HCl (0.1 M). The PpPD adsorbent performed optimally for eight cycles and still retained about 80% adsorption efficiency at the 10th cycle using an initial Cr(VI) concentration of 100 mg/L. Treatment with the regenerants showed irreversible oxidation reaction for the adsorbents while still removing Cr(VI) for several cycles. To investigate the toxicological impact on seed germination due to contact with used adsorbents, phytotoxicity test was investigated. Seed germination severely diminished to 35% and 14% (respective to control) in the presence of P-p-PD-MMT and P-p-PD. In paper III polypyrrole-clay composite was synthesized and also proved to be an effective adsorbent for Cr(VI) removal. A percentage Cr(VI) removal of 99% was obtained at pH 2 using adsorbent dosage of 0.15g for 100 mg/L Cr(VI) concentration for 3h in a batch mode. Due to its excellent adsorption properties, the composite was regenerated using different varied concentrations of eluents (NaOH, NH4OH, HCl, NH4Cl and HNO3). Desorption and regeneration using 0.01 M NaOH and 0.5 M HCl gave more regeneration cycles where the first 5 regeneration efficiencies were still greater than 80%. EDX determined the elemental components of the polypyrrole-clay composite before and after Cr(VI) adsorption. It demonstrated a significant decrease of Cl- ions after adsorption which is attributed to ion exchange mechanism between Cl- ions and Cr(VI) during the adsorption process. Investigation of the adsorption behaviour revealed a decrease in thermal stability of the composite after several adsorption cycles while treating the adsorbent with the regenerants as a result of material oxidation and deterioration due to Cr(VI) exposure in acidic medium and the impact of the regenerants. According to FT-IR analysis, polypyrrole-clay bands shifted to a higher wavenumber after Cr(VI) adsorption due to the change in skeletal vibrations as a result of Cr(VI) species adsorbed onto its surface Paper (IV) described synthesized adsorbents for phosphate removal. The study presented the development and performance of two sets of poly(phenyelenediamine) (PPD) isomers synthesized from ammonium persulphate ((NH4)2S2O8) and potassium dichromate (K2Cr2O7) as oxidants. The chemical structure of the adsorbents were determined using FT-IR, TGA and XRD. Amorphous morphology dominated in all the polymers with poly(m-phenylenediamine) PmPD being more amorphous and PpPD was the least. Batch adsorption studies showed improved adsorption capacity for K2Cr2O7 synthesized polymers. K2Cr2O7 oxidant played a major role in providing trivalent chromium metal which improved the phosphate uptake. This is attributed to the Lewis acid-base interaction where trivalent chromium acts as an acid and phosphate ions serve as a base. Batch adsorption results showed that solution pH, contact time and initial concentration influenced phosphate adsorption with the maximum adsorption capacities of 143 mg/g, 217 mg/g and 69.0 mg/l for PoPD, PmPD and and PpPD adsorbents, respectively. Adsorption reached equilibrium at about 300 min at an optimum pH of 2.0. The adsorption isotherms were described by Langmuir isotherm and the kinetic data were described better by pseudo-second order kinetic rate model implying adsorption onto homogeneous surfaces and the mechanism of adsorption was attributed to chemisorption. Desorption was conducted on the meta substituted PPD using NaOH (0.05 M) which displayed effective desorption capacity and exhibited commendable adsorption for re-use. The adsorbent also proved to be selective to phosphate ions at the background of much higher concentrations of sulphate and nitrate anions due to the presence of Coulombic and Lewis-acid-base interactions. In paper (V), remediation of phosphate ions was examined using modified bentonite clay as an adsorbent. Modification was achieved by incorporating Fe, Ni and Co metal salts using precipitation method. Adsorbents were characterized by FT-IR and XRD. The results showed significant amorphosity for metal modified bentonite compared to the parent bentonite. The adsorption capacity for all studied bentonite-based materials increased with increasing initial phosphate concentration and adsorption mechanisms were influenced by the solution pH. The maximum adsorption capacity of 6.57 mg/g, 20.88 mg/g, 29.07 mg/g and 46.95 mg/g were obtained for Bent, Fe-Bent, Ni-Bent and Co-Bent, respectively. The adsorption rate fitted pseudo-second order for all adsorbents. Langmuir isotherm model described the phosphates removal for all adsorbents at an optimum pH of 3.MT 201

Solar UV-Photooxidation as sample pretreatment step in trace metals analysis in Natural water samples by differential pulse Voltammetric methods

This dissertation describes the application of Solar ultraviolet radiation to the digestion of dissolved organic matter in natural water samples such as river water prior to the determination of trace metals by stripping voltammetric techniques. We studied that solar UV can destroy dissolved organic matter that hinders voltammetric determination by either complexing the metal ions or by interacting with the electrode materials and optimized time required for Solar UV irradiation at a given UV intensity such as mid-latitude (Europe) or tropical regions such as Africa