This study explored the barrel technique for biochar production, comparing it with laboratory-prepared biochar by evaluating the effect on sugarcane-growing soil quality. Different sugarcane biomass (bagasse, trash, and mini mill waste) derived biochar was prepared using a muffle furnace at three different temperatures (300, 450, and 600 °C) and with the barrel technique. Biochar was characterized by yield, pH, electrical conductivity (EC), proximate and ultimate analysis, scanning electron microscopy (SEM) analysis, and Fourier-transform infrared spectroscopy (FT-IR) characterization. A pot experiment was conducted with soil amendments with biochar (bagasse biochar pyrolyzed at 450 °C–BBC-450 and bagasse biochar prepared from barrel technique–BBC-BT) at a 2.5 • Barrel technique biochar significantly improves sugarcane soil quality. • Biochar boosts soil pH, EC, OC, and nutrient levels. • BBC-BT showed the highest soil quality index in 90 days.

The present study evaluated the feasibility of Pandanus kaida (watekeiya) leaves as an adsorbent for removing Cu(II) ions from aqueous solutions using Atomic Absorption Spectroscopy to quantify the residual Cu(II) concentration. The main focus of the study was to investigate the effect of initial metal concentration, contact time, pH, particle size, and adsorbent dosage on the removal of Cu(II) ions by watekeiya leaf powder using batch adsorption studies. An equilibrium adsorption capacity of 5.69 mg g-1 was observed at an optimum pH of 6 for the initial metal concentration of 20.0 ppm, 0.300 g/100 mL adsorbent dosage with 250 mu m particle size, within a contact time of 120 minutes at 30 $<^> \circ C$ degrees C. The optimum conditions for the maximum removal of Cu(II) by the adsorbent were found to be: 0.300 g in 100 mL of the adsorbate solution at pH 6 for 120 minutes contact time at a temperature of 30 $<^> \circ C$ degrees C and with a particle size of 250 mu m. The kinetic studies determined the pseudo-second-order model as the best-fit model, suggesting a chemisorption mechanism for the rate-determining step. Adsorption isothermal studies determined the Langmuir model as the best-fitted model. The maximum monolayer adsorption capacity obtained from the Langmuir model at 30 $<^> \circ C$ degrees C was 15.45 mg g-1. FTIR analysis indicated the presence of hydroxyl, amide, C-O, and C = O functional groups on the adsorbent. The lack of a considerable shift in peak positions in FTIR analysis reflects that physisorption is involved in the process as well. SEM analysis revealed an irregular surface structure with pores that can aid in adsorption.

A novel organic-inorganic hybrid nanomaterial-based fluorescent chemosensor was synthesized by functionalizing rice husk-derived nanosilica with 3-(aminopropyl)triethoxysilane (APTES) and then grafting it with para-aminobenzoic acid, benzaldehyde, and indole organic moieties, respectively, to detect Ag+ ions in the aqueous medium. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), fluorescence spectroscopic techniques, and thermogravimetric analysis (TGA) were used to characterize the synthesized material. The synthesized ligand showed highly selective and sensitive fluorescence-enhanced, "Turn-ON" chemosensor activity towards Ag+ ions at an excitation wavelength of 355 nm, with observable variations in fluorescence intensity compared to other metal ions. The detection limit for Ag+ was 1.94 × 10–4 M, and the limit of quantification was calculated as 6.49 × 10–4 M. These findings suggest that the silica-supported indole derivative (Indole-APTES@nanosilica) can be utilized as a sensitive and selective, Turn-ON fluorometric chemosensor for detecting Ag+ ions.

Environmental hazard from open dumping is a severe problem occurring around the world. The composition of waste from most of developing countries accounts for more than 50% of organic matter. Prolonged incomplete handling of solid waste or lack of management at disposal sites has caused significant environmental and social challenges across the world in these regions such as pollution of nearby water supplies, pollution of groundwater, enhanced mosquito breeding sites, unintentional landfill gas fire, microbial pollution from atmospheric dust, atmospheric contaminantscreating unpleasant and highly toxic gases and Volatile Organic Carbons (VOCs), emission of green house gases (GHGs) damage to vegetation, air pollution leading to global warming etc. Among the sources of water pollution, open dumpsites have been identified as one of the significant threats. A significant amount of metal release namely Cd, As, Cr, Fe can be occurred by the disposal methods such as open dumps. Disastrous events like "dumpslides", fires have been recorded worldwide causing casualties due to the mismanagement of open dumpsites. Composting, resource recovery, waste mining, use of bio covers are useful techniques which can be applied to existing open dumpsites. This review will address the environmental pressure from open dump sites as and the futuristic approaches in waste management aligning with Sustainable Development Goals (SDG) and circular economy.

The haphazard disposal of plastic waste has become a severe environmental problem. The low degradability of plastics in nature has resulted in the production of tiny plastic fragments by physical and chemical degradation of large plastic debris, and fragments in the range of 1 to 1000 μm are known as microplastics (MPs). MPs can be considered one of the worst forms of plastic waste damaging the environment. Their sorption and desorption of both organic and inorganic pollutants leads to bioaccumulation via food chains and can cause detrimental effects. In addition, MPs function as vectors of certain chemical pollutants, including persistent organic pollutants (POPs), perfluoroalkyl substances (PFAS), phthalate esters, pharmaceuticals, and heavy metals. It has been identified that the type of polymer, crystallinity, size of plastic particles, pH of the medium, age, and degree of weathering of plastic debris influence the interaction of chemical pollutants with MPs. MP-bound pollutants can desorb from plastic to organisms, causing various issues when those organisms ingest plastics. This chapter will elaborate on the interaction of chemical contaminants with MPs, mechanisms driving the interaction, and future approaches for handling environmental issues related to MPs.

Fluoride is beneficial for human health only in a narrow concentration range. Over the years, many analytical techniques have been developed to quantify fluoride in a variety of sample matrices. In this research, fluoride concentrations of twenty (20) natural water samples determined by SPADNS (SPA) and Eriochrome Cyanine R (ECR) colorimetric methods were evaluated to ascertain whether these methods can produce comparable fluoride concentrations. According to the paired t test for comparing individual differences, the two datasets are different at 95% confidence level suggesting that the two analytical methods produce statistically different fluoride concentrations for the analysed water samples. The potential interferences of Al3+, Ca2+, and Mg2+ on the fluoride analysis was evaluated using 0.85 mg L-1 fluoride standard solutions spiked with various amount of the abovementioned metal ions. The highest interference was observed with Al3+ ions, which underestimated the fluoride concentration by 26% and 23% for ECR and SPA methods respectively at 20.0 mg L-1 Al3+ concentrations. The minimum interference was observed for Ca2+ ions which underestimated the fluoride concentration by 8% and 7% for ECR and SPA methods respectively at 100.0 mg L-1 Ca2+ concentrations. Acid distillation resulted in the samples spiked with Ca2+ and Mg2+ ions in the range of 0.50 to 100.0 mg L-1 reaching the theoretical concentration of 0.85 mg L-1. Acid distillation also worked well for the Al3+- fortified samples, except for Al3+ concentration at 20 mgL(-1). The efficiency of the acid distillation method was also tested with three (03) natural water samples. The fluoride concentration increased significantly after the acid distillation; however, even after the acid distillation, statistically comparable fluoride concentrations were not observed.

Tropical countries face considerable economic losses due to mosquito-borne diseases which can be effectively combatted using plant-based mosquito repellents. Therefore, using a questionnaire survey, we selected the 25 top-ranked common but underutilized aromatic plants with mosquito repellent ability in Sri Lanka to investigate the rural sector's willingness to cultivate and supply them. Cinnamomum verum, Citrus aurantiifolia, Citrus sinensis, Citrus reticulata, Aegle marmelos, and Ocimum tenuiflorum were the common species thus identified. The willingness to cultivate and supply aromatic plants with mosquito repellent ability varied between 88% and 60%. The Chi-squared test indicated a significant association between gender and willingness to cultivate and supply these plants. Men had a higher willingness (82%). Persons formally educated up to elementary school level had the highest willingness (85%). The willingness from households with many non-income-generating members was 100%. The random forest model developed in this study identifies farmers' willingness to cultivate and supply aromatic plants with mosquito repellent properties. It was trained using an upsampling strategy. Our findings aid in understanding the scenarios involved with introducing, cultivating, and supplying aromatic plants.

Iron is one of the most microbiologically and chemically important metals in natural waters. The biogeochemical cycling of iron is significantly influenced by the redox cycling of Fe(II) and Fe(III). Because of the unique chemistry of iron, it is often needed to analyze iron at nano-molar concentrations. This article describes a reverse flow injection analysis (rFIA) based method with ferrozine spectrophotometric detection to quantify total iron concentration in stream water at nanomolar concentrations. The rFIA system has a 0.65 nM detection limit and a linear dynamic range up to 1.40 mu M for the total iron analysis. The detection limit was achieved using a 1.0 m long liquid waveguide capillary flow cell, 1.50 m long knotted reaction coil, 87.50 mu L. injection loop and a miniature fiber optics spectrophotometer. The optimized colorimetric reagent has 1.0 mM ferrozine, 0.1 M ascorbic acid, 1.0 mM citric acid and 0.10 M acetate buffer adjusted to pH 4.0. The best sample flow rate is 2.1 mL min(-1) providing a sample throughput of more than 15 samples h(-1). The linear dynamic range of the method can be adjusted by changing the volume of the injection loop. The rFIA manifold was assembled exclusively from commercially available components.

Padaviya Wewa Reservoir constructed in 2nd century BC is an important traditional reservoir in Sri Lanka. The construction and the use of these traditional Sri Lankan reservoirs are different from modern large-scale hy-droelectric and multi-purpose reservoirs in Sri Lanka and the rest of the world. The hydrochemistry of these unique water bodies has been rarely studied and understood. In this study, depth-wise distribution of Fe, Mn, Zn, Cd, and As and their correlation with pH, dissolved oxygen, conductivity, temperature, BOD, COD, and total phosphate were investigated to identify the mechanisms that drive the water quality in Padaviya Wewa Reservoir. There is a well distinguishable chemical gradient from the surface to the bottom of the water column suggesting that Padaviya is not a well-mixed water body even though the maximum water depth during the study period was 4.75 m. There was a strong negative correlation between Fe, Mn, Zn, and Cd and DO in both surface and bottom waters. In addition, a strong positive correlation between Fe, Mn, Zn, Cd, and As, and total phosphate was observed in bottom waters. The suggested driving force behind the depth-wise distribution of chemical species is intense biological activities in the reservoir. The weak thermal stratification is strengthened by photosynthesis at the surface waters and organic matter degradation at bottom of the reservoir. The end-result of these biological activities are oxygen rich surface waters with low concentrations of nutrients and metal ions and oxygen depleted bottom waters with higher concentrations of nutrients and metal ions.

The proper management of municipal solid waste for the reduction of its potential impacts on the environment is one of the most challenging issues faced by the world. In this study, a comprehensive characterization of leachate and groundwater was carried out surrounding the Oum Azza sanitary landfill in Morocco to assess their potential risks to human health. The groundwater quality was analysed using quality indices and chemometric expertise. For this purpose, spatiotemporal variation of sixteen (16) physico-chemical parameters and nine (9) heavy metals (Cd, Pb, Ni, Cu, Cr, Hg, Ni, Zn, and Fe) in groundwater and leachate were studied. Experimental data showed elevated leachate contamination potential (LPI = 29.14) surpassed the permissible limits for discharge of leachate. Besides, the application of WQI (27.47–214.58), Nemerow index (0.72–6.17), irrigation quality indices (SAR, MHR, %Na, KI, and PI), and spatial distribution revealed the unsuitability of most of the groundwater samples in vicinity of the landfill area for drinking and irrigation purposes. However, the carcinogenic and non-carcinogenic risks are still within acceptable limits for residential receptors. The multivariate statistical (PCA and HCA) analysis suggested that the deterioration of groundwater quality was mainly originated from anthropogenic sources related to landfill leachate. This study proved an alarming threat of the groundwater in vicinity of the sanitary landfills due to leachate pollution. It is important to note that despite the fact that the landfill is a sanitary landfill and provided with liners, leachate contamination potential is inevitable. Thus, it is important to continuously monitor the groundwater quality surrounding the landfill. The study also recommended emphasizing on the status and conditions of geomembrane used in the landfill liner systems to prevent leachate percolation into the groundwater.

Chitosan is a well-studied biomaterial which has been widely used for environmental applications as an efficient natural polymer for the adsorption and removal of metal ions. Owing to its unique properties, chitosan shows good metal-binding behavior toward several different metal ions such as Cu2+, Zn2+, Cd2+, Ni2+, Co2+, and Ca2+. Chemical modifications with the introduction of functional groups have been carried out extensively and thereby producing various chitosan derivatives to increase the selectivity and adsorption capacity toward metal ions. The present work focuses on two such monofunctional derivatives, namely, carboxymethyl chitosan (CMC) and ethylenediaminetetraacetic acid chitosan (EDTA-CS) which have been recognized as excellent adsorbents for metal removal. The main objective of this study was to synthesize a new bifunctional chitosan derivative, namely, ethylenediaminetetraacetic acid–carboxymethyl chitosan (EDTA-CMC) by attaching both carboxymethyl and EDTA functional groups on the polymer backbone and thereby enhancing its metal-binding properties. The bifunctional derivative synthesis was conducted by combining the procedures of synthesis of CMC and EDTA-CS. Newly synthesized EDTA-CMC derivative was characterized by Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscope analysis, and thermogravimetric analysis. Adsorption properties of EDTA-CMC were investigated with Cu2+ ions which produced an adsorption capacity of 111.90 mg g−1 for 1000.0 mg/L and 12.20 mg g−1 for 10.00 mg/L Cu2+ solutions. The preliminary results revealed that EDTA-CMC is an effective adsorbent than CMC to remove Cu2+ in aqueous samples. The effects of pH, initial concentration, and mass of the adsorbent in the adsorption process were studied. Under the optimized parameters of an adsorbent dosage of 10.00 mg and pH 5.5, a comparable maximum adsorption capacity up to 112.44 mg g−1 was achieved with a 150.00 mg/L of Cu2+ solution. Furthermore, EDTA-CMC showed good adsorption performance even after five cycles of regeneration.

The dye and pigment industry have become a well-established industry now because color has been very close to man since ancient times. Color is being widely used to showcase the quality life. Recent reports estimate that greater than 0.7 million tons of dyes are manufactured annually all around the world. After the dyeing process, dye effluents are released into the environment from industries without proper treatment, and the amount is estimated to 1 to 1.5×105tons per year. Due to stability and complex structure, most of the dyes are resistant to degradation and they are highly toxic. It is required to remediate dye contaminated water effluents to protect natural water resources and ensure the well-being of the living organisms. In this study, an effort has been taken to develop biochar from low-cost precursor, cinnamon (Cinnamomum zeylanicum) wood and its ability to remove model dyes rhodamine B (RDB) and malachite green (MG) were investigated. Prepared biochar was characterized by Fourier Transform Infra-Red (FTIR) spectroscopy to identify the surface functional groups. The X-ray diffraction (XRD) analysis confirmed the amorphous structure of cinnamon wood biochar (CWBC). Batch adsorption experiments were carried out to investigate the optimum conditions such as adsorbent dosage, contact time, pH, and initial dye concentration. The best conditions for the maximum adsorption for the RDB dye was achieved in less than 15 minutes, using 0.20 g adsorbent dose in 100.00 ml dye solution at pH 3.09. The MG dye was adsorbed to CWBC effectively within 60 minutes, 0.01 g of adsorbent dosage in 100.00 ml dye solution at the pH 6.75. The maximum adsorption capacity for the RDB removal was obtained as 2.01 mgg-1and that was 403.06 mgg-1for the MG removal. Langmuir model explained the dye adsorption behavior and also it suggested that, adsorption mechanism was favorable in MG adsorption. Freundlich isotherm fitted best to explain the adsorption of RDB. Thus, the results confirm the feasibility of CWBC to be used as an efficient adsorbent in the removal of RDB and MG from aqueous solutions. Keywords: Rhodamine B, Malachite green, Cinnamon wood biochar, Adsorption, Dye removal

We have synthesized two ligand systems, N(SO2)(R1)dpa (L1) and N(SO2)(R2)dpa (L2), where R1 = biphenyl and R2 = azobenzene, which are sulfonamide derivatives of the NNN-donor chelating dipicolylamine. Both L1 and L2 can be used as sensors for detecting Fe3+ and are highly sensitive and selective over a wide range of common cations. Time-dependent density functional theory (TDDFT) calculations confirmed that the key excitations of L2 and the [Fe(L2)(H2O)3]3+ model complex involve -R2-unit-based π and π* charge transfer. L2 demonstrates a relatively high photostability, a fluorescence turn-on mechanism, and a detection limit of 0.018 μM with 1.00 μM L2 concentration, whereas L1 has a detection limit of 0.67 μM. Thus, both ligands have the potential to be used as fluorosensors for the detection of Fe3+ in aqueous solutions.

The COVID-19 pandemic created numerous issues, particularly in Southeast Asia, and the recovery needs strong actions with new economic paths. The Sri Lankan government is also trying to help those who have lost their sources of income. Involving with the trade of medical and aromatic plants (MAPs) bearing unique medical properties will be important in that aspect. Extracted and isolated some secondary metabolites from plants developed life-saving medicine, flavonoids, repellents, cosmetics, and scents with enormous economic potential. India, China, and other Asian countries dominate the global MAP trade. However, Sri Lanka is yet to enter the global MAP market by utilising its abundant plant life. Determining rural communities’ willingness to participate in such programmes is crucial. The same authors identified 127 lesser-known potential MAPs as insect repellents by interviewing traditional ayurveda practitioners and subject experts. The current study investigated the willingness of the rural sector in six districts in Sri Lanka (Matara, Rathnapura, Kurunegala, Badulla, Hambanthota, and Batticaloa) using a structured questionnaire survey for 480 households. Cinnamomum verum, Citrus aurantifolia, C. sinensis, C. reticulata, Aegle marmelos, and Ocimum tenuiflorum Sub-type Rama were the most abundant top five plant species. The questionnaire also sought information on respondents' demographics, the availability of agronomic plants, MAPs, in their homegardens and their willingness to cultivate and supply medicinal plants. Binomial logistic regression was used to determine the effects of the respondent’s district, gender, age, education, total family revenue, availability of agronomic crops, land space available for the cultivation of MAPs, number of non-income-generating family members, members contribute to agriculture, external employees recruited as labourers. Hosmer-Lemeshow test indicated that the model reasonably fits with the data (p=0.77). In this case, district (p<0.05) and gender (p<0.05) were statistically significant while the other variables were not. Compared to Badulla District, the odds of willingness to grow and supply MAPs are approximately five times greater in Batticaloa District, four times greater in Hambantota, Kurunegala, and Matara districts and three times greater in Rathnapura District. Subsequently, the odds of the willingness of males to grow and supply MAPs was greater than females. Finally, it can be concluded that encouraging MAPs cultivation in rural areas will benefit post-pandemic populations while facilitating global trade, which is expected to reach USD 5 trillion by 2050. Keywords: Medicinal aromatic plants, Bioeconomy, Post-pandemic economic future, Rural economy, Indigenous knowledge

The escalating loads of municipal solid waste (MSW) end up in open dumps and landfills, producing continuous flows of landfill leachate. The risk of incorporating highly toxic landfill leachate into environment is important to be evaluated and measured in order to facilitate decision making for landfill leachate management and treatment. Leachate pollution index (LPI) provides quantitative measures of the potential environmental pollution by landfill leachate and information about the environmental quality adjacent to a particular landfill. According to LPI values, most developing countries show high pollution potentials from leachate, mainly due to high organic waste composition and low level of waste management techniques. A special focus on leachate characterization studies with LPI and its integration to treatment, which has not been focused in previous reviews on landfill leachate, is given here. Further, the current review provides a summary related to leachate generation, composition, characterization, risk assessment and treatment together with challenges and perspectives in the sector with its focus to developing nations. Potential commercial and industrial applications of landfill leachate is discussed in the study to provide insights into its sustainable management which is original for the study.

Contamination of ground and surface waters by landfill leachate is a prime environmental concern. The present research assesses chemical composition of leachate generated in the Karadiyana open dumpsite in Sri Lanka and the groundwater pollution caused by the landfill. The leachate pollution index (LPI) of Karadiyana is 34.00, suggesting that it has the potential to contaminate the environment. The nitrate, ammonia, and total phosphate concentrations in leachate varied in the range of 20.70 to 167.80, 376.55 to 580.33 and 10.00 to 84.00 mg/L respectively. Four major groups, namely, tryptophan- and tyrosine-like protein fractions, and fulvic and humic fractions were identified in leachate using fluorescence data. The bio chemical oxygen demand (HOD) to chemical oxygen demand (COD) ratio of leachate in the present study varied between 0.39 and 0.49 which categorizes leachate into intermediate age with medium biodegradability. This observation was further verified by the average pH and COD values of leachate; 6.81 +/- 0.08 and 2221 +/- 45 mg/L, respectively. Only one out of ten dug wells located in a radius of about a kilometer from Karadiyana dumpsite can be classified as good water for drinking purposes though eight of ten are used for drinking at the moment. All ten dug wells exceeded the WHO recommended nitrate level.

Electrokinetic remediation (EKR), also known as electro-reclamation, electrokinetics, or electrokinetic soil processing, is a promising technique used to treat contaminated soils and sediments. EKR applies low-intensity direct current to contaminated porous matrices including soils, sediments, and sludge. The electric field enables assembling and transporting contaminants at electrodes. EKR was first used to remove inorganic contaminants from soil/sediment. Later, it was successfully adapted to treat soils and sediments contaminated with organic contaminants like hydrocarbons, herbicides, chlorinated solvents, and polycyclic aromatic hydrocarbons. EKR has unique advantages over conventional techniques: it can be used both ex situ and in situ and applied to heterogeneous and low-permeability matrices. It has been reported that combined technologies such as EKR combined with chemical oxidation/reduction and permeable reactive barriers (PRBs) are more efficient in implementing the treatment process.

Open dumping of municipal solid waste (MSW) imposes severe environmental threats in which landfill leachate generation is considered as the predominant. This study aims on treating landfill leachate using a pilot scale biochar based barricade and wetland system. Biochar was derived from MSW of Karadiyana dumpsite, using the pyrolysis barrel method, providing approximately 500 degrees C of pyrolysis temperature within 2 h of time duration. Characterization of biochar was done using Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) techniques. The wetland was constructed using a mixture of biochar and sand in 1:2 volume ratio, whereas the barricade was filled with 7.5 kg biochar and laterite. For additional removal, Canna indica was planted in the wetland. Leachate was diluted in a 1:1 ratio, allowing it to flow through the system at a rate of 10 ml/min. The analysis was continuously carried out for 7 days. The results showed 99.97, 83.95 and 92.73% removal for ammonium-N, phosphate and COD respectively. Thus, suggesting the potential upscaling of the system with further improvements through testing different ratios of biochar and leachate flow rates.

Cobalt (Co2+) is an essential constituent in the human body while excessive exposure leads to severe systemic toxic reactions which highlight the importance of developing effective methods to detect Co2+ ions. A simple and highly efficient fluorescence enhanced turn OFF-ON chemosensor was synthesized to detect the paramagnetic Co2+. The ligand, N-((1H-indol-3-yl)(phenyl)methyl)aniline (L), was synthesized in 92% yield by means of hydrated ferric chloride catalyzed one -pot multicomponent microwave irradiation in the presence of Indole, benzaldehyde, and aniline as reactants. The major green principles of waste prevention, high atom economy (94.3%), green solvent, higher energy efficiency, and catalysis were the highlights of the ligand synthesis. The ligand exhibited remarkable fluorescence enhancement with Co2+ and a turn ON ratio of over 160-fold in MeOH/H2O (at pH 3.5) solution at an excitation wavelength of 369 nm in the Ultra-Violet range. The detection limit of L- Co2+ was 2.2 μM. The excitation and the emission spectra indicated stoke’s shift of 93 nm which supports the fluorescence enhancement observed in L- Co2+ with respect to the free ligand. The Job’s plot indicated fluorometric sensing of Co2+ ascribed to the complex formation with a stoichiometric ratio of 2:1 (L- Co2+). Furthermore, the high linearity (r2 =0.992) observed in the Benesi Hildebrand plot in a wide concentration range of 0.5−80 μM confirmed the above stoichiometric ratio. The association constant (Ka) for the L-Co2+ was determined to be 8.382 ×1 04 M−1 ± 5.8 ×103M−1.The prepared Co2+ fluorometric probe indicated long-term stability in −18 ℃ up to 45 days. Furthermore, the presence of Fe2+ and Fe3+ in the medium with Co2+ exhibited an interference effect in the fluorescence intensities. Upon further concentration studies, it was evident that the interference of Fe2+ and Fe3+ starts around 10.00 μM and rises exponentially. Keywords: MCR, Green synthesis, Fluorescent Chemo-sensor, Turn OFF-ON, Cobalt (II), indole derivatives