Free CO2 Research Articles

Nuclear Magnetic Resonance Study of CO2 Capture by Fluoroalkylamines: Ammonium Ion pKa Depression via Fluorine Modification and Thermochemistry of Carbamylation.

We are developing energy-efficient and reversible carbon capture and release (CCR) systems that mimic the Lys201 carbamylation reaction in the active site of ribulose-1,5-bisphosphate carboxylase-oxygenase (RuBisCO). The multiequilibria scenario ammonium ion Xa ⇌ amine Xb ⇌ carbamic acid Xc ⇌ carbamate Xd requires the presence of both free amine and CO2 for carbamylation and is affected by the pKa(Xa). Two fluorination strategies aimed at ammonium ion pKa depression and low pH carbamylation were analyzed with (2,2,2-trifluoroethyl)butylamine 2b and 2,2-difluoropropylamine 3b and compared to butylamine 1b. The determination of K1 and ΔG1 of the carbamylation reactions requires the solution of multiequilibria systems of equations based on initial conditions, 1H NMR measurements of carbamylation yields over a wide pH range, and knowledge of K2-K5 values. K2 and K3 describe carbonic acid acidity, and ammonium ion acidities K4 were measured experimentally. We calibrated carbamic acid acidities K5 based on the measured value K6 of aminocarbamic acid using isodesmic reactions. The proton exchange reactions were evaluated with ab initio computations at the APFD/6-311+G* level in combination with continuum solvation models and explicit solvation. The utilities of 1-3 will be discussed as they pertain to the development of fluorine-modified RuBisCO-mimetic reversible CCR systems.

EFFECT OF PHYSICO-CHEMICAL POLLUTION OF RIVER DEORANIA ON THE METABOLIC ACTIVITIES OF PREDATORY FISH, CHANNA PUNCTATUS AT DISTRICT BAREILLY (U.P.) INDIA

The present study was aimed at assessing the value of different physicochemical parameters of two sites (i.e. site A is clear and considered a control site while site B is loaded with heavy pollution so it is considered as experimental site) during December 2005-2006 and 2020-2021 in extreme months of different seasons. The analysis showed that the discharge of a major part of domestic wastes of Bareilly City, city refuge, debris, animal and human excreta and industrial effluents, enhanced the pollution load at site B and thereby enhanced the abnormal metabolic activities of fish. Whereas at clear site A the metabolic activities of fish were normal. In the present study, the following parameters i.e. temperature, colour, transparency, dissolved oxygen (DO), free CO2, biochemical oxygen demand (BOD), salinity, total dissolved solids (TDS), level of glycogen, reducing sugar level, total protein level, level of amino acids, activity of alkaline phosphatase and acid phosphatase enzymes were analysed.

Impact of aquifer properties on the extent and timeline of CO2 trapping

AbstractGeologic CO2 sequestration in porous saline aquifers is a promising approach to reducing atmospheric concentrations of CO2. Reactive transport simulations provide the opportunity to analyze which factors influence geochemical reactivity in the reservoir, understand those most important for promoting CO2 trapping, and assess individual sites. Field‐scale aquifer characterization is time and resource intensive such that here, reactive transport simulations are leveraged to enhance understanding of selected aquifer properties including porosity, permeability, depth of storage, and carbonate mineralogy on the overall CO2 trapping potential to better select sites promoting geochemical reactivity for CO2 trapping. There are different mechanisms for sequestrating CO2. Once injected, CO2 will dissolve into the brine to create an acidic environment, resulting in the dissolution of pre‐injection formation minerals. Released ions can reprecipitate as secondary minerals. The dissolved CO2 and mineralized CO2 are considered as a more secure form of CO2 trapping in this study compared to the free supercritical CO2. Here, a framework leveraging a controlled set of field scale simulations is developed to facilitate rapid, optimized site selection. Simulations vary aquifer properties to understand the impact of each unique property on CO2 trapping, tracking, and comparing the amount of supercritical, aqueous, and mineralized CO2. The rate at which the CO2 injected into the aquifer is converted to aqueous or mineralized CO2 is newly defined here as the sequestration efficiency and used to compare simulation results. The reservoir depth and fraction of carbonate minerals in the formation are shown to be more important factors than reservoir porosity and permeability in affecting CO2 trapping. However, the impact of aquifer properties on the evolution of injected CO2 depends on the stage of the sequestration project. © 2023 Society of Chemical Industry and John Wiley & Sons, Ltd.

Effect of De-Icing Chemicals on Concrete Scaling: The Role of Storage Water.

This paper deals with the effect of the character of the water used for the water storage of concrete test specimens on the results of tests for resistance to de-icing chemicals. Two experiments were conducted to investigate the effect of the content of free CO2 in water and leaching of calcium hydroxide from concrete on the test results. In the first experiment, the resistance of mortars to water and de-icing chemicals was investigated. It was found that the character of the water storage, i.e., fresh water vs. previously used water, can significantly affect the test results. The second experiment focused on investigating the effect of the content of free CO2 in water on the test results. It was found that the content of free CO2 in the water can statistically significantly influence the test results. In conclusion, the paper shows that the character of the water used for water storage of concrete test specimens and the content of free CO2 in water are essential factors that can significantly affect the results of concrete resistance tests to de-icing chemicals. Further research is needed to understand these influences and their potential use to improve the resistance of concrete.

Imaging of CO2 and Dissolved Inorganic Carbon via Electrochemical Acidification-Optode Tandem.

Dissolved inorganic carbon (DIC) is a key component of the global carbon cycle and plays a critical role in ocean acidification and proliferation of phototrophs. Its quantification at a high spatial resolution is essential for understanding various biogeochemical processes. We present an analytical method for 2D chemical imaging of DIC by combining a conventional CO2 optode with localized electrochemical acidification from a polyaniline (PANI)-coated stainless-steel mesh electrode. Initially, the optode response is governed by local concentrations of free CO2 in the sample, corresponding to the established carbonate equilibrium at the (unmodified) sample pH. Upon applying a mild potential-based polarization to the PANI mesh, protons are released into the sample, shifting the carbonate equilibrium toward CO2 conversion (>99%), which corresponds to the sample DIC. It is herein demonstrated that the CO2 optode-PANI tandem enables the mapping of free CO2 (before PANI activation) and DIC (after PANI activation) in complex samples, providing high 2D spatial resolution (approx. 400 μm). The significance of this method was proven by inspecting the carbonate chemistry of complex environmental systems, including the freshwater plant Vallisneria spiralis and lime-amended waterlogged soil. This work is expected to pave the way for new analytical strategies that combine chemical imaging with electrochemical actuators, aiming to enhance classical sensing approaches via in situ (and reagentless) sample treatment. Such tools may provide a better understanding of environmentally relevant pH-dependent analytes related to the carbon, nitrogen, and sulfur cycles.

The impact of electricity-carbon market coupling on system marginal clearing price and power supply cost.

In this study, we assessed the impacts of the benchmark designs of emissions allowance allocation in China's national carbon emissions trading system with plant-level data and further estimated the marginal clearing price and power supply cost in Guangdong power market under electricity-carbon market coupling with unit commitment and economic dispatch model. We find that the existing allowances benchmark would result in a considerable surplus of allowances at about 222 Mt. But the benchmarking and exemplary levels on the heat rate of power supply would motivate thermal power units to reduce CO2 emissions. Under a tight balance of supply and demand in Guangdong, peaking thermal power plants will become the marginal clearing units and higher clearing prices will add to the revenue of lower cost inframarginal renewable energy power units. However, the combined impact of electricity-carbon market coupling would cause the marginal clearing price fluctuates obviously from 0 to 1159 CNY/MWh. Compared to the baseline scenario with free CO2 allowances allocation, the efficiency of thermal power utilization would decrease by 23%-59% and the net revenue per MWh power supply of coal-fired power units would decrease by 275%-325% under the stress scenario. Our study suggests that setting a more stringent allowances allocation benchmark for carbon price discovery is necessary. As electricity-carbon market coupling changes the role of coal-fired power plants to provide flexibility service and decrease their revenues, it calls for further market designs on proper reimbursement of flexible resources, under which the electricity market can effectively achieve the synergy among accommodating new energy, ensuring resource adequacy, and delivering cost efficiency. In addition, the synergy can be enhanced by formulating a tax program, which can promote renewable energy investment.

Hydrochemistry of Kupinde Lake at the Lesser Himalaya in Karnali Province, Nepal

Hydrochemical assessment of the freshwater lakes provides important insights into the sources of dissolved ions, geochemical processes, and anthropogenic activities taking place in the environment. This study focuses on the assessment of hydrochemistry and water quality of Kupinde Lake, Karnali Province, Nepal. Surface water samples were collected from 24 different locations of the lake in October 2021 and analyzed for 18 different physico-chemical parameters. The pH, temperature, electrical conductivity and total dissolved solids were measured on-site, and concentration of major ions (Ca2+, Mg2+, Na+, K+, NH4+, HCO3-, Cl-, SO42-, PO43-, NO3-), including hardness and free CO2 were measured in the laboratory. The results revealed that lake water was alkaline with abundance of the major ions in the following order: Ca2+ > Mg2+ > Na+> K+ > NH4+ and HCO3- > Cl- > SO42- > PO43- > NO3- for the cations and anions, respectively. The lake water was dominated by Ca-HCO3, indicating calcium carbonate dominated lithology in the area. Gibb’s plot and Piper diagram illustrated rock weathering as the most dominant process in controlling the hydrochemistry of the lake basin. The suitability of water for drinking and irrigation was determined using geochemical indices and WHO standards. The results indicated that the Kupinde Lake water could be used for drinking and irrigation purposes in terms of measured hydrochemical variables.

The generation mechanism of CO and CO2 in coal spontaneous combustion by mathematical statistical and other methods

At present, the mechanism of CO and CO2 production in coal spontaneous combustion is controversial. With the hope of exploring the generation mechanism of CO and CO2 in the low-temperature oxidation of coal, in this study, the correlation between the relative contents of three active functional groups, –CH3/–CH2, -C = O, and –COOH and the generation law of CO and CO2 in the low-temperature oxidation of coal samples with different metamorphic degrees was explored by means of principal component analysis, Pearson linear analysis, and Fourier transform infrared spectroscopy. The results indicate that –CH3/–CH2, -C = O, and –COOH in low-rank lignite (HC) are significantly correlated with the concentrations of CO and CO2. The -C = O and –COOH in medium-rank bituminous coal (BC) are closely correlated with the concentrations of CO and CO2. The concentrations of CO and CO2 in high-rank anthracite (CQ) show the highest correlation with the relative content of –CH3/–CH2, followed by their correlation with the relative content of -C = O, and their correlation with the relative content of –COOH is relatively low. Thus, it can be concluded that the generation mechanism of CO and CO2 varies with the metamorphic degrees of coal in coal spontaneous combustion. CO and CO2 generated from low-rank HC mainly come from continuous generation and oxidation of inherent and secondary alkyl chains and those generated from medium-rank BC mainly come from the oxidation of oxygen-containing functional groups. Besides, for high-rank CQ, CO is mainly generated from the process in which alkyl chains in coal oxidize to form carbonyl groups which then break to form CO, and a small part of CO comes from the coal-oxygen free radical reaction. As for CO2, its sources are more complex. A big portion of CO2 comes from the free radical reaction and CO2 may also come from the direct conversion of CO at high temperature and in the presence of water. Finally, the reaction mechanism of C = O· and ·OH free radicals was studied by quantum chemical calculation. The calculation results reveal that the free radical reaction can occur spontaneously and release a certain amount of heat under certain conditions, thus playing a positive role in promoting coal spontaneous combustion.

Monitoring the dynamics of acid mine drainage affected stream surface water hydrochemistry at Jaintia Hills, Meghalaya, India.

Streams are pristine natural life-thriving water sources for people living in the mountainous proximity of NE India, where water scarcity is a common occurrence in most villages and towns. In the last few decades, factors like coal mining had drastically reduced the usability of stream water in the region; as such, an attempt has been made to assess the spatiotemporal variation of stream water chemistry affected by acid mine drainage (AMD) at Jaintia Hills, Meghalaya. The water variables were subjected to a multivariate statistical technique of principal component analysis (PCA) to understand their condition at each sampling point while comprehensive pollution index (CPI) and water quality index (WQI) was incorporated to assess the quality status. Maximum WQI was recorded in S4 (541.14) during summer, while minimum value was estimated in winter at S1 (14.65). Throughout the seasons, the WQI revealed "Good" quality in S1 (unimpacted stream), while the impacted streams (S2, S3, and S4) exhibited a "Very poor" to "Water unsuitable for drinking" status. Similarly, in S1, the CPI showed a ranged value of 0.20 to 0.37, presenting a water quality status of "Clean to Sub-Clean," whereas, CPI of the impacted streams indicated "Severely polluted" status. In addition, PCA bi-plot presented higher affinity of free CO2, Pb, SO42-, EC, Fe, and Zn in AMD-impacted streams than in unimpacted streams. The result demonstrates the environmental issues induced by coal mine waste and in particular, stream water being severely affected by AMD in mining areas of Jaintia Hills. Thus, measures to stabilized the mine repercussions and cumulative effects on the water bodies need to be formulated by the government, as stream water will remain the primary water source for the tribal communities in this region.

CO2 -induced chloroplast movement in one cell-layer moss leaves.

CO2 -induced chloroplast movement was reported in the monograph by Gustav Senn in 1908: unilateral CO2 supply to the one cell-layered moss leaves induced the positively CO2 -tactic periclinal arrangement of chloroplasts. Here, using the model moss plant Physcomitrium patens, we examined basic features of chloroplast CO2 -tactic relocation with a modernized experimental system. The CO2 relocation was light-dependent and, especially, CO2 relocation in red light was substantially dependent on photosynthetic activity. In blue light, CO2 relocation was mainly dependent on microfilaments while microtubule-based movement was insensitive to CO2 , whereas in red light, both cytoskeletons contributed redundantly to CO2 relocation. The CO2 relocation was observed not only when the two leaf surfaces were exposed to CO2 -free air versus CO2 -containing air, but also by exposing them physiologically relevant differences in CO2 concentrations. In the leaves placed on the surface of a gel sheet, chloroplasts avoided the gel side and positioned in the air-facing surface, and this phenomenon was also shown to be photosynthesis dependent. Based on these observations, we propose a hypothesis that the threshold light intensity between the light-accumulation and -avoidance responses of the photorelocation would be increased by CO2 , resulting in the CO2 -tactic relocation of chloroplasts.

The “Oxygen Sink” of Bamboo Shoots Regulates and Guarantees the Oxygen Supply for Aerobic Respiration

The amazingly rapid growth of bamboo shoots requires strong respiration and provides a large amount of energy and intermediate metabolites. Strong aerobic respiration requires a large amount of O2. This raises the following question: What is the source and mechanism of O2 supply to meet aerobic respiration? However, currently, this remains unknown. The underground buds (US), the 2-m-high overground buds (AS), and the 8-m-high growth arrest buds (HS) of bamboo (Phyllostachys prominens) were collected to represent their different stages of growth and development. The fifth bamboo shoot node at each stage was sealed by two membranes, and treated in a polyethylene zip-lock bag filled with air (21% O2 + 79% N2) and nitrogen (100% N2) for 1.5 h. The concentrations of free O2 and CO2 in the shoot cavities in polyethylene zip-lock bags, and the ethanol content in the shoot body before and after treatment were determined. In addition, the photosynthetic rates of the fifth bamboo internodes of 1 y/o, 2 y/o and 3 y/o bamboo in the field were measured. The results indicated that: (1) When treated with air and nitrogen, US, AS and HS mainly exhibited aerobic respiration, and there was almost no anaerobic respiration; (2) When treated with air, 59.66%, 54.47% and 45.84% of the O2 in the aerobic respiration of US, AS and HS came from the polyethylene zip-lock bag, 0.06%, 0.57% and 0.650% came from the shoot cavity, but 40.28%, 44.96% and 53.51% of the O2 was of an unknown source; (3) Treated by nitrogen, 0.19%, 4.71% and 4.79% of O2 in aerobic respiration of US, AS and HS came from shoot cavity, while the other 99.808%, 95.290% and 95.21% of O2 came from unknown sources; and (4) The photosynthesis of the fifth internodes of 1 y/o, 2 y/o and 3 y/o bamboo generated little oxygen that could not absolutely meet the huge O2 supply for aerobic respiration. It was concluded that the respiration of P. prominens shoots in its different growth and development stages was dominated by aerobic respiration. O2 supply pathways were mainly via the sheath stomata; however, there was little absorption from dissolved O2 in the soil water and little supply produced by shoot/stem photosynthesis. It was found that the large supply of oxygen in the aerobic respiration of bamboo shoots and young bamboo was of an unknown source under air treatment and nitrogen treatment, i.e., 40.28%–53.51% and 95.21%–99.81% of oxygen in the aerobic respiration of bamboo shoots and young bamboo was of unknown origin, respectively. Therefore, we proposed that bamboo shoots may exhibit the phenomenon of acting as an “oxygen sink”, which can provide a large amount of O2 from unknown sources to ensure the rapid growth of bamboo shoots and young bamboo.

Physico-chemical Analysis of some major ponds in relation to fish production of district Kaushambi Uttar Pradesh

Present study is aimed to explore the physico-chemical characteristics of four major ponds of district Kaushambi. There are many ponds in district Kaushambi. Most of the ponds have been devastated due to anthropogenic activities. The ponds which are selected for the study are three from Ichhna village and one from Saraiakil village in Nevada block of tehsil-Chail in Kaushambi. The three ponds from Ichhna village are Telan, Potaniha and Khewkhar and one pond from Saraiakil village are selected. The physico-chemical parameters are water transparency, temperature, dissolved oxygen, ph., Free CO2, alkalinity and total solids etc. The study was conducted during the month of March 2021 to February 2022. It was noted to have alkaline water throughout the year. The biodiversity and the production of fish depend upon the physico-chemical characteristics of the ponds.

Enhanced Surface Charge Localization Over Nitrogen-Doped In2O3 for CO2 Hydrogenation to Methanol with Improved Stability

Indium oxide (In2O3) is active and promising for selective hydrogenation of CO2 to methanol. However, it suffers from over-reduction at elevated temperatures, causing deactivation. Herein, a nitrogen-doped In2O3 (N–In2O3) catalyst was prepared using a plasma-intensified nitrogen-doping technology. It is confirmed that nitrogen doping is effective for the stabilization of In2O3. The doped nitrogen enhances the surface charge localization, which inhibits the over-reduction on the oxide surface and limits the generation of excessive surface oxygen vacancies. The doped nitrogen also serves as the active site, synergistically with surface oxygen vacancy, which leads to an enhanced dissociation of CO2 to adsorbed CO* intermediates. The electron-rich nitrogen causes a strong adsorption of CO on N–In2O3 and inhibits the formation of free CO. A significantly improved methanol selectivity with a higher turnover frequency (TOF) is thus achieved on N–In2O3, compared to the un-doped In2O3. For example, at 21,000 cm3 h–1 gcat–1, 300 °C, and 5 MPa, the TOF of N–In2O3 reaches 37.0 h–1 with methanol selectivity of 75.1%, while the TOF of the un-doped In2O3 is only 16.0 h–1 with methanol selectivity of 62.3%. Different from pristine In2O3, N–In2O3 takes the CO hydrogenation route for CO2 hydrogenation to methanol. This explains the reason why the N–In2O3 catalyst possesses improved selectivity for CO2 hydrogenation to methanol.

Research on the feasibility of storage and estimation model of storage capacity of CO2 in fissures of coal mine old goaf

The concept of the carbon cycle in the old goaf of a coal mine based on CO2 utilization and storage was put forward adhering to the principle of low-carbon development, utilization of space resources in old goafs, and associated gas resources development. Firstly, the evolution characteristics of overburden fissures in the goaf of the case was studied using a two-dimensional physical similarity simulation test, the sealing performance of the caprocks after stabilization was analyzed, and the fissures were counted and classified. Then, the process of gaseous CO2 injection in the connected fissure was simulated by Ansys Fluent software, and the migration law and distribution characteristics of CO2 under the condition of gaseous CO2 injection were analyzed. Finally, the estimation models of free CO2 storage capacity in the old goaf were constructed considering the proportion of connected fissure and the effectiveness of CO2 injection. The CO2 storage capacity in the old goaf of the case coal mine was estimated. The results showed that a caprock group of “hard-thickness low-permeability hard-thickness” was formed after the caprock-fissures system in the goaf of the case tended to be stable vertically. The connected fissure, occlude cracks, and micro-fractures in the goaf accounted for 85.5%, 8.5%, and 6% of the total fissures, respectively. Gaseous CO2 first migrated to the bottom of the connected fissure after CO2 was injected into the goaf, then spread horizontally along the bottom of the connected fissure after reaching the bottom, and finally spread longitudinally after filling the bottom of the entire connected fissure. The theoretical and effective storage capacities of free CO2 at normal temperature and pressure in the old goaf of the case were 9757 and 7477 t, respectively. The effective storage capacity of free CO2 at normal temperature and pressure in the old goaf after all minefield mined was 193404 t. The research can provide some reference for the coal mining industry to help the goal of “carbon peaking and carbon neutrality”.

Physico-Chemical Analysis Of Fish Farming Ponds Of Darbhanga, Bihar, India

  Safe drinking water is a fundamental human right & basic need of individuals. Water quality is an important criteria for productivity of pond. The study was designed to assess the quality of pond water of Dighi Pond & Harahi pond of Darbhanga, Bihar, with reference to physic-chemical parameters including turbidity, conductivity, dissolve O2, free CO2, PH, potassium, zinc, iron, sodium, chloride and hardness. The results were evaluated and compared with both ponds water quality. It is found that based on physic-chemical parameters, both ponds water is not suitable for fish farming. &nbsp

Evolution of anthracite nanopores with CO2 adsorption at different pressures by synchrotron radiation small angle X-ray scattering

As a porous medium, coal has a strong adsorption capacity for CO2. Nanopore is the main adsorption space of coal reservoir. To study the evolutionary characteristics of nanopores in coals with CO2 adsorption, in situ small angle X-ray scattering experiments of anthracite at different CO2 adsorption pressures were carried out. The change of scattering intensity ratio RI in nanopores with different sizes were analyzed. The porosity, specific surface area and average aperture were quantitatively characterized. The research shows that the 5 nm pores is more susceptible to higher CO2 pressure, while the scattering phenomenon in the 15 nm pores changes most obviously at lower CO2 pressure. The deformation sensitivity of 35–75 nm pores to CO2 adsorption is consistent. The scattering data in anthracite show a positive Porod deviation. CO2 will become dense with increasing pressure, and its filling of nanopores makes some scattering phenomena become invisible to X-ray. There will be a new boundary between dense CO2 and free CO2, which affects the fluctuation of electron density between two-phase systems. There is a positive correlation between the Porod deviation of the scattering data and the CO2 pressure. In the process of CO2 adsorption, the dynamic deformation of anthracite nanopores is obvious, resulting in synchronous changes of porosity and specific surface area. CO2 adsorption pressure is negatively correlated with porosity and specific surface area, but positively correlated with the average aperture. The decrease of CO2 pressure leads to the gradual recovery of nanopore deformation. However, at different evolution stages of the same CO2 pressure, the porosity, specific surface area and average aperture of anthracite are inconsistent. Irreversible damage to anthracite nanopores is produced with CO2 adsorption. The evolution of nanopores is the result of the superposition of CO2 compression and adsorption.

Study of the impact of various porous media on pore space utilization and CO2 storage by injection of microbubbles into oil reservoirs

CO2 capture and storage technology have the potential to help reach net zero emissions. CO2-enhanced oil recovery (CO2 EOR) is a favourable method. Limited pilot testing has provided preliminary evidence that the unique physical properties of gas microbubbles (MBs) can be used to improve pore utilization efficiency. In this study, supercritical CO2 injection at 0.05 mL/min into sand samples with different grain sizes under reservoir conditions was investigated by nuclear magnetic resonance (NMR). The spatial distribution of the CO2 and oil and the dynamic pore occupancy mechanism were determined for the first time, and the results from normal bubbles (NBs) and MBs were compared. The results show a more significant left shift of the transverse relaxation time in the case of MB injection, which means that CO2 can easily occupy a wide range of large pore spaces. Dynamic changes in the oil volume in the four types of pores classified by the transverse relaxation time indicate that the oil in large pores is flushed earlier when MB is injected and that the CO2 saturation in minimal pores (T2 relaxation time range from 5 ms to 100 ms) and small pores (T2 relaxation time range from 100 ms to 500 ms) increases. The cumulative oil volume fraction decreases by 9.0% when injecting MBs. From the perspective of carbon storage, the gas storage potential is significantly enhanced within low-permeability sand when injected with MBs. The maximum volume of free CO2 was enhanced by 16.9% in this case. In addition, the storage efficiency is enhanced up to 5.1% for low-permeability sand and 1.6% for medium-permeability sand. However, bubble flow is not as advantageous in high-permeability sand. Considering dissolution trapping, the storage efficiency reaches 26.3%.

Analysis of Water Quality of Hatirjheel Lake, Dhaka, Bangladesh

The study assessed the status of water quality parameters for an urban water body (Hatirjheel Lake) in Dhaka, the Capital city of Bangladesh. Nine different water samples were collected from nine points of the lake during the dry season in January 2021. Water quality parameters such as pH, electrical conductivity (EC), total dissolved solids (TDS), total suspended solids (TSS), total alkalinity, total acidity, total hardness, Ca2+ hardness, free CO2, and dissolved oxygen (DO) were determined for the samples. The status of the parameters is pH (6.51-7.05), EC (510-600 μS.cm-1), TDS (450-590 ppm), TSS (0.0-0.034 mg.L-1), total alkalinity (80-392 mg.L-1), total acidity (224-500 mg.L-1), total hardness (348-452 mg.L-1), Ca2+ hardness (74-162 mg.L-1), free CO2 (730-1170 mg.L-1), DO (2.7-5.5 mg.L-1). However, the DO value at some points of the lake is too less (2.7 mg.L-1 and 3.7 mg.L-1) than the standard value (> 5-6 mg.L-1) of ECR, DoE, which might not be healthy for any water body and aquatic ecosystem. Other water quality parameters are within the permissible limit of WHO and ECR, DoE.

Assessment of Zooplankton and Physico-chemical Parameters of Upper River Benue, Adamawa State, Nigeria

Between January and June, 2022 some physico-chemical and biological conditions of Upper River Benue were assessed at five selected sites on monthly basis between 6:00 – 10:00a.m. A total of 9.849 ×104 organisms/L was recorded for zooplankton abundance. Rotifera was observed to have a total abundance of 39.9%, followed by Cladocera contributed a total of 33.45%, while the least was Decapoda gave 1.37%. The higher number of taxa (25) was recorded at site V. The abundance of individuals was highest at site IV. Twenty-seven species (27) species of zooplankton were identified during the study period ranging from elven Rotifera, nine Cladocera, five Copepoda, one Ostracoda and one Decapoda. The order of dominance of the zooplankton of Upper River Benue is Rotifera>Cladocera>Copepoda>Ostracoda>Decapoda with Brachionus caudate, Bosmina longirostis and daphnia being the most dominant (6.94%) of the total zooplankton of Upper River Benue. The physico-chemical parameters results revealed that temperature, pH, electrical conductivity, transparency, dissolved oxygen, free CO2, alkalinity were within recommended acceptable limit except ammonia, phosphorus and nitrogen were higher than recommended acceptable limit. However, no significant difference was found between the seasons in terms physico-chemical paraneters and zooplankton distribution (P>0.05). The study showed the reservoir to be eutrophic with moderate water quality, high ecological and pass chemical status, with diverse assemblages of zooplankton. It was recommended that there should be continuous monitoring of the biological and physico-chemical status of the river to ascertain the long-term impact of anthropogenic inputs to take remedial measures so as to ensure the health of aquatic life.

Assessment of the Present State and Future Fate of River Saraswati, India: Water Quality Indices and Forecast Models as Diagnostic and Management Tools

AbstractWater quality assessment is key to the conservation and management of rivers. River Saraswati, a distributary of the river Ganga, serves as a lifeline to many villages in the district Hooghly in West Bengal, India. As the river is gradually dying due to diverse man‐made pollution, ten water quality parameters in two sampling spots (PR‐1 and PR‐2) in the river are monitored month‐wise from March 2017 to February 2020, and these are compared with those from a reference pond. The water quality index (WQI) is determined for the two riverine spots and the reference pond based on the Canadian Council of Ministers of Environment WQI (CCMEWQI) and weighted arithmetic WQI, respectively. In addition to actual observations, three different forecasting methods, exponential smoothing, autoregressive integrated moving average, and artificial neural network, are used to predict WQI for the next two years. This study indicates that free CO2, dissolved oxygen, and turbidity are the key parameters to evaluate this river's anthropogenic stress and health. The actual and forecasted results reflect the precipitous degradation of CCMEWQI in PR‐2. Therefore, the immediate intervention of all stakeholders is required to adopt an integrated and comprehensive river management plan to save the river from utter obliteration.