All Stories

  1. Magnetic multifunctional nanomaterials for enhanced transverse chemical and bioanalytical applications – A review
  2. Carbon quantum dots conjugated with metal hybrid nanoparticles as advanced electrocatalyst for energy applications – A review
  3. Kinetic & thermodynamic studies of green fuel additive solketal from crude glycerol over metakaolin clay catalyst
  4. Tribological characterisation of graphene hybrid nanolubricants in biofuel engines
  5. Development and testing of environment friendly nanohybrid coatings for sustainable agriculture technologies
  6. Prospects of renewable energy potentials and development in Bosnia and Herzegovina – A review
  7. Unveiling drug induced nephrotoxicity using novel biomarkers and cutting-edge preventive strategies
  8. Performance and emission characteristics of double split injection biodiesel engine with intake air throttling
  9. Photocatalytic and structure evaluation of g-C3N4/carbon microspheres and melam/dimelem intermediates under white LED and UVA-Vis irradiation
  10. Novel therapeutical approaches based on neurobiological and genetic strategies for diabetic polyneuropathy – A review
  11. Synergetic removal of hazardous pollutants from aqueous environment using lignocellulosic biosorbents
  12. Functionalised mesoporous biosorbents for efficient removal of hazardous pollutants from water environment
  13. Effects of Zofenopril on Arterial Stiffness in Hypertension Patients
  14. Graphitic carbon nitride derived probes for the recognition of heavy metal pollutants of environmental concern in water bodies
  15. Optimization and performance characteristics of diesel engine using green fuel blends with nanoparticles additives
  16. Dynamic and Steady-State Simulation Study for the Stabilization of Natural Gas Condensate and CO2 Removal through Heating and Pressure Reduction
  17. Functional biotransformation of phytoestrogens by gut microbiota with impact on cancer treatment
  18. High-temperature rheological behavior and non-isothermal pyrolysis mechanism of macerals separated from different coals
  19. Improving estimation of water soil erosion by introducing lithological formation for environmental remediation
  20. Effect of Diabetic Neuropathy on Reparative Ability and Immune Response System
  21. Nanostructured Materials for Drug Delivery and Tissue Engineering Applications
  22. Eco‐friendly three‐dimensional hydrogels for sustainable agricultural applications: Current and future scenarios
  23. Surface engineered functional biomaterials for hazardous pollutants removal from aqueous environment
  24. Production of adsorbent for removal of propranolol hydrochloride: Use of residues from Bactris guineensis fruit palm with economically exploitable potential from the Colombian Caribbean
  25. Removal of enalapril maleate drug from industry waters using activated biochar prepared from Butia capitata seed. Kinetics, equilibrium, thermodynamic, and DFT calculations
  26. Organic Covalent Interaction‐based Frameworks as Emerging Catalysts for Environment and Energy Applications: Current Scenario and Opportunities
  27. Cellular therapeutic potential of genetically engineered stem cells in cancer treatment
  28. A review of the antibiotic ofloxacin: Current status of ecotoxicology and scientific advances in its removal from aqueous systems by adsorption technology
  29. Covid-19 a triggering factor of autoimmune and multi-inflammatory diseases
  30. Vanillin cross-linked hydrogel membranes interfacial reinforced by carbon nitride nanosheets for enhanced antibacterial activity and mechanical properties
  31. Effects of intestinal flora on pharmacokinetics and pharmacodynamics of drugs
  32. Multifunctional cobalt oxide nanocomposites for efficient removal of heavy metals from aqueous solutions
  33. Parametric optimization and structural feature analysis of humic acid extraction from lignite
  34. A review on production and implementation of hydrogen as a green fuel in internal combustion engines
  35. Effect of nanoparticles additives on tribological behaviour of advanced biofuels
  36. Highly effective sustainable membrane based cyanobacteria for uranium uptake from aqueous environment
  37. Hybrid valorization of biodiesel production using sustainable mixed alcohol solvent
  38. Discovering untapped microbial communities through metagenomics for microplastic remediation: recent advances, challenges, and way forward
  39. Editorial: Emerging approaches for sustainable management for wastewater
  40. Bioinspired engineered nickel nanoparticles with multifunctional attributes for reproductive toxicity
  41. Functional bioinspired nanocomposites for anticancer activity with generation of reactive oxygen species
  42. Synergistic interaction of metal loaded multifactorial nanocatalysts over bifunctional transalkylation for environmental applications
  43. Bioprospecting microalgae for biofuel synthesis
  44. Fabrication of nanocage structured based electrocatalyst for oxygen evolution reactions
  45. Effect of copper doping on plasmonic nanofilms for high performance photovoltaic energy applications
  46. Environmental and toxicological concerns associated with nanomaterials used in the industries
  47. A comprehensive review on green perspectives of electrocoagulation integrated with advanced processes for effective pollutants removal from water environment
  48. Smart nano-architectures as potential sensing tools for detecting heavy metal ions in aqueous matrices
  49. Assessment of three decades treated wastewater impact on soil quality in semi-arid agroecosystem
  50. Flexible Green Supply Chain Management in Emerging Economies: A Systematic Literature Review
  51. Advancements of sequencing batch biofilm reactor for slaughterhouse wastewater assisted with response surface methodology
  52. An improved MOPSO algorithm for optimal sizing & placement of distributed generation: A case study of the Tunisian offshore distribution network (ASHTART)
  53. Cellulose acetate based sustainable nanostructured membranes for environmental remediation
  54. Polyvinyl alcohol and aminated cellulose nanocrystal membranes with improved interfacial compatibility for environmental applications
  55. Thermodynamic valorisation of lignocellulosic biomass green sorbents for toxic pollutants removal
  56. Energy efficiency improvement potentials through energy benchmarking in pulp and paper industry
  57. Phytoremediation of heavy metals in soil and water: An eco-friendly, sustainable and multidisciplinary approach
  58. Plastic Circular Economy Framework using Hybrid Machine Learning and Pinch Analysis
  59. Multifunctional Smart Conducting Polymers–Silver Nanocomposites-Modified Biocellulose Fibers for Innovative Food Packaging Applications
  60. Corrigendum to “Enhanced lignin extraction and optimisation from oil palm biomass using neural network modelling” [Fuel 293 (2021) 120485]
  61. Superior removal of humic acid from aqueous stream using novel calf bones charcoal nanoadsorbent in a reversible process
  62. Integrated electrocoagulation-tight ultrafiltration for river water decontamination: The influence of electrode configuration and operating pressure
  63. Energy, exergy, sustainability and economic analysis of waste tire pyrolysis oil blends with different nanoparticle additives in spark ignition engine
  64. Effet de l’application du fongicide sur la productivité de l’eau du blé tendre
  65. Esterases and Their Industrial Applications
  66. Broadening the Scope of Biocatalysis Engineering by Tailoring Enzyme Microenvironment: A Review
  67. Optimization of engine out responses with different biodiesel fuel blends for energy transition
  68. Synthesis of green nano sorbents for simultaneous preconcentration and recovery of heavy metals from water
  69. Composite of methyl polysiloxane and avocado biochar as adsorbent for removal of ciprofloxacin from waters
  70. Algae based green biocomposites for uranium removal from wastewater: Kinetic, equilibrium and thermodynamic studies
  71. Synthesis and Characterization of High-Efficiency Halide Perovskite Nanomaterials for Light-Absorbing Applications
  72. Nanotechnology-based controlled release of sustainable fertilizers. A review
  73. IDF21-0423 Michigan neuropathy screening for assessing diabetes in participants and correlation to the immune response
  74. Preface
  75. Biorenewable Nanocomposites as Robust Materials for Energy Storage Applications
  76. Exploring Marine as a Rich Source of Bioactive Peptides: Challenges and Opportunities from Marine Pharmacology
  77. Energy, exergy, thermoeconomic and sustainability assessment of tire pyrolysis oil in common rail direct injection diesel engine
  78. Microbial fuel cells a state-of-the-art technology for wastewater treatment and bioelectricity generation
  79. Advantages and Challenges of Biodegradable Electronic Devices
  80. Adsorptive remediation of naproxen from water using in-house developed hybrid material functionalized with iron oxide
  81. Sustainable nanotechnology based wastewater treatment strategies: achievements, challenges and future perspectives
  82. Synthesis and toxicity assessment of environment friendly high yield ceria nanoparticles for biosafety
  83. Hydrothermally engineered Eriobotrya japonica leaves/MgO nanocomposites with potential applications in wastewater treatment
  84. Recent advances in chemically and biologically synthesized nanostructures for colorimetric detection of heavy metal
  85. Microbial adaptation to different environmental conditions: molecular perspective of evolved genetic and cellular systems
  86. Comparative effects of conventional and nano-enabled fertilizers on morphological and physiological attributes of Caesalpinia bonducella plants
  87. Green synthesis of zero-valent iron nanoparticles and loading effect on activated carbon for furfural adsorption
  88. Biomass-derived renewable materials for sustainable chemical and environmental applications
  89. Design strategies for the synthesis of deep eutectic solvents
  90. Effects of zeolite-based nanoparticles on the biodegradation of organic materials
  91. Production of carbon-based adsorbents from lignocellulosic biomass
  92. Role of laccase in the pulp and paper industry
  93. Treatment of pulp and paper industry waste effluents and contaminants
  94. Biosynthesis of SiO2 nanoparticles using extract of Nerium oleander leaves for the removal of tetracycline antibiotic
  95. Two dimensional MXenes as emerging paradigm for adsorptive removal of toxic metallic pollutants from wastewater
  96. Esterases as emerging biocatalysts: Mechanistic insights, genomic and metagenomic, immobilization, and biotechnological applications
  97. Silver Conductive Threads-Based Embroidered Electrodes on Textiles as Moisture Sensors for Fluid Detection in Biomedical Applications
  98. Valorization of Solketal Synthesis from Sustainable Biodiesel Derived Glycerol Using Response Surface Methodology
  99. Green synthesis and evaluation of calcium-based nanocomposites fertilizers: A way forward to sustainable agricultural
  100. Adsorptive remediation of environmental pollutants using magnetic hybrid materials as platform adsorbents
  101. Hydrothermally engineered enhanced hydrate formation for potential CO2 capture applications
  102. Effects of conservation and standard tillage on soil physico-chemical properties and overall quality in a semi-arid agrosystem
  103. Unprecedented Impacts of Aviation Emissions on Global Environmental and Climate Change Scenario
  104. Tailored functional materials as robust candidates to mitigate pesticides in aqueous matrices—a review
  105. Nano-structured dynamic Schiff base cues as robust self-healing polymers for biomedical and tissue engineering applications: a review
  106. Preparation and Characterisation of Sustainable Wood Plastic Composites Extracted from Municipal Solid Waste
  107. Self-Compassion and Empathy as Predictors of Happiness among Late Adolescents
  108. Environmental and health impacts of spraying COVID-19 disinfectants with associated challenges
  109. Comparison of acidic leaching using a conventional and ultrasound-assisted method for preparation of magnetic-activated biochar
  110. Comparative Effect of Inoculation of Phosphorus-Solubilizing Bacteria and Phosphorus as Sustainable Fertilizer on Yield and Quality of Mung Bean (Vigna radiata L.)
  111. Supercritical water oxidation of phenol and process enhancement with in situ formed Fe2O3 nano catalyst
  112. Heavy metals content in ashes of wood pellets and the health risk assessment related to their presence in the environment
  113. Thermal Analysis Technologies for Biomass Feedstocks: A State-of-the-Art Review
  114. 3D Guided Dental Implant Placement: Impact on Surgical Accuracy and Collateral Damage to the Inferior Alveolar Nerve
  115. Treatment of Emerging Water Pollutants by Fenton and Modified Fenton Processes
  116. In-situ hydrogenolysis of glycerol using hydrogen produced via aqueous phase reforming of glycerol over sonochemically synthesized nickel-based nano-catalyst
  117. Hydrothermally engineered Ni–CuC hybrid nanocomposites: Structural and morphological investigations with potential fuel catalytic applications
  118. Nano architectured cues as sustainable membranes for ultrafiltration in blood hemodialysis
  119. Feedback Control of Melt Pool Area in Selective Laser Melting Additive Manufacturing Process
  120. Chemical Thermodynamics and Kinetics of Thiophenic Sulfur Removed from Coal by Microwave: A Density Functional Theory Study
  121. Applications Characteristics of Different Biodiesel Blends in Modern Vehicles Engines: A Review
  122. Effect of Calcium Doping Using Aqueous Phase Reforming of Glycerol over Sonochemically Synthesized Nickel-Based Supported ZrO2 Catalyst
  123. IL-1β in Correlation to the Common Diabetic Complications
  124. Synthesis of Zeolite supported bimetallic catalyst and application in n-hexane hydro-isomerization using supercritical CO2
  125. Effect of Intake Air Temperature and Premixed Ratio on Combustion and Exhaust Emissions in a Partial HCCI-DI Diesel Engine
  126. Cellulose-deconstruction potential of nano-biocatalytic systems: A strategic drive from designing to sustainable applications of immobilized cellulases
  127. Liquid value-added chemicals production from aqueous phase reforming of sorbitol and glycerol over sonosynthesized Ni-based catalyst
  128. Solvent extraction and performance analysis of residual palm oil for biodiesel production: Experimental and simulation study
  129. Starch and polyvinyl alcohol encapsulated biodegradable nanocomposites for environment friendly slow release of urea fertilizer
  130. Preparation of hybrids of wood sawdust with 3-aminopropyl-triethoxysilane. Application as an adsorbent to remove Reactive Blue 4 dye from wastewater effluents
  131. Green synthesis of ZnO nanoparticles from Syzygium Cumini leaves extract with robust photocatalysis applications
  132. Integrated Optimal Design of Permanent Magnet Synchronous Generator for Smart Wind Turbine Using Genetic Algorithm
  133. Waste sugarcane bagasse‐derived nanocatalyst for microwave‐assisted transesterification: Thermal, kinetic and optimization study
  134. Sustainable Hydrates for Enhanced Carbon Dioxide Capture from an Integrated Gasification Combined Cycle in a Fixed Bed Reactor
  135. Metal Organic Frameworks Derived Sustainable Polyvinyl Alcohol/Starch Nanocomposite Films as Robust Materials for Packaging Applications
  136. Cellulose acetate-polyvinyl alcohol blend hemodialysis membranes integrated with dialysis performance and high biocompatibility
  137. Comments on “Reasonable calculation of the thermodynamic parameters from adsorption equilibrium constant, Journal of Molecular Liquids 322 (2021) 114980.”
  138. Nano and micro architectured cues as smart materials to mitigate recalcitrant pharmaceutical pollutants from wastewater
  139. Jatropha Curcas Biodiesel: A Lucrative Recipe for Pakistan’s Energy Sector
  140. Tribological Behaviour of Graphene Nanoplatelets as Additive in Pongamia Oil
  141. A Study of Hot Climate Low-Cost Low-Energy Eco-Friendly Building Envelope with Embedded Phase Change Material
  142. Synthesis of a novel nanocomposite based on date stones/CuFe2O4 nanoparticles for eliminating cationic and anionic dyes from aqueous solution
  143. Enhancing food packaging with antibacterial membranes using eco-friendly materials
  144. Fully solar powered Doncaster Sheffield Airport: Energy evaluation, glare analysis and CO2 mitigation
  145. A Review on Recycling and Reutilization of Blast Furnace Dust as a Secondary Resource
  146. Optimization of Fuel Injection Parameters of Moringa oleifera Biodiesel-Diesel Blend for Engine-Out-Responses Improvements
  147. Effects of ultrasound irradiations time over Ni–Mo/γ-Al2O3 catalyst synthesis for 1,3 – Propanediol selectively via aqueous phase reforming of glycerol
  148. Energy evaluation and environmental impact assessment of transportation fuels in Pakistan
  149. Enhanced lignin extraction and optimisation from oil palm biomass using neural network modelling
  150. Exploring relationship between environmentalism and consumerism in a market economy society: A structured systematic literature review
  151. Novel strategies to reduce engine emissions and improve energy efficiency in hybrid vehicles
  152. Selective removal of lead ions from aqueous solutions using SiO2–MoO3: Isotherm, kinetics and thermodynamic studies
  153. Thrombolytic and cytotoxic activity of different bioactive extracts of E. coli
  154. Valorisation and emerging perspective of biomass based waste-to-energy technologies and their socio-environmental impact: A review
  155. Tailor made Functional Zeolite as Sustainable Potential Candidates for Catalytic Cracking of Heavy Hydrocarbons
  156. Preparation of active coke combining coal with biomass and its denitrification performance
  157. Effect of protic ionic liquid treatment on the pyrolysis products of lignin extracted from oil palm biomass
  158. Part load operation of natural gas fired power plant with CO2 capture system for selective exhaust gas recirculation
  159. Covalent organic frameworks as robust materials for mitigation of environmental pollutants
  160. Potential of Waste Cooking Oil Biodiesel as Renewable Fuel in Combustion Engines: A Review
  161. Fuel Injection Responses and Particulate Emissions of a CRDI Engine Fueled with Cocos nucifera Biodiesel
  162. Coupling of electrocoagulation and powder activated carbon for the treatment of sustainable wastewater
  163. Activated Carbon Impregnated by Zero-Valent Iron Nanoparticles (AC/nZVI) Optimized for Simultaneous Adsorption Furfural: Green Synthesis, Regeneration, Characterization, and Adsorption-Desorption Studies
  164. Socio-Economic and Environmental Impacts of Biomass Valorisation: A Strategic Drive for Sustainable Bioeconomy
  165. A novel method for removing organic sulfur from high-sulfur coal: Migration of organic sulfur during microwave treatment with NaOH-H2O2
  166. Impact of COVID-related lockdowns on environmental and climate change scenarios
  167. Tailored functional polymeric vesicles as smart nanostructured materials for aqueous monitoring of transition metal cations
  168. Tribological Behaviour and Lubricating Mechanism of Tire Pyrolysis Oil
  169. Current Status and Potential of Tire Pyrolysis Oil Production as an Alternative Fuel in Developing Countries
  170. Impacts of Different Tillage Practices on Soil Water Infiltration for Sustainable Agriculture
  171. Sustainable Conversion of Renewable Energy Sources
  172. Activation of Nano Kaolin Clay for Bio-Glycerol Conversion to a Valuable Fuel Additive
  173. Sustainable Wastewater Treatment Using Electrocoagulation Process Coupled With Powdered Activated Carbon
  174. Effect of acid catalysts on hydrothermal carbonization of Malaysian oil palm residues (leaves, fronds, and shells) for hydrochar production
  175. Design and feasibility study of novel paraboloid graphite based microbial fuel cell for bioelectrogenesis and pharmaceutical wastewater treatment
  176. Process analysis of improved process modifications for ammonia-based post-combustion CO2 capture
  177. Mimic Enzyme Based Cellulose Nanocrystals/PVA Nanocomposite Membranes for Enrichment of Biogas as a Natural Gas Substitute
  178. A Comprehensive Review on Oil Extraction and Biodiesel Production Technologies
  179. Adsorption: Fundamental aspects and applications of adsorption for effluent treatment
  180. Removal of micropollutants from municipal wastewater using different types of activated carbons
  181. Exergoeconomic optimization of a binary geothermal power plant
  182. Evaluation of current and future solvents for selective lignin dissolution–A review
  183. Solution Combustion Synthesis of Transparent Conducting Thin Films for Sustainable Photovoltaic Applications
  184. Making hydrocarbon fuels from carbon dioxide and water in molten salts
  185. Catalytic Activity of Pt Loaded Zeolites for Hydroisomerization of n-Hexane Using Supercritical CO2
  186. Development of biomass derived highly porous fast adsorbents for post-combustion CO2 capture
  187. Removal of captopril pharmaceutical from synthetic pharmaceutical-industry wastewaters: Use of activated carbon derived from Butia catarinensis
  188. An Experimental Investigation on Tribological Behaviour of Tire-Derived Pyrolysis Oil Blended with Biodiesel Fuel
  189. Short Communication: Is one performing the treatment data of adsorption kinetics correctly?
  190. Carbon nanotubes assisted analytical detection – Sensing/delivery cues for environmental and biomedical monitoring
  191. Biogas upgrading with novel cellulose nano-crystals and polyvinyl amine nanocomposite membranes
  192. Catalytic reforming of oxygenated hydrocarbons for the hydrogen production: an outlook
  193. Effect of Post Weld Heat Treatment on the Microstructure and Electrochemical Characteristics of Dissimilar Material Welded by Butter Method
  194. Electrochemical study of different membrane materials for the fabrication of stable, reproducible and reusable reference electrode
  195. Steam electrolysis in molten hydroxides for hydrogen
  196. Exergetic, Economic and Exergo-Environmental Analysis of Bottoming Power Cycles Operating with CO2-Based Binary Mixture
  197. The effect of variable operating parameters for hydrocarbon fuel formation from CO2 by molten salts electrolysis
  198. Thermodynamic and kinetic study of synthesised graphene oxide-CuO nanocomposites: A way forward to fuel additive and photocatalytic potentials
  199. Photocatalytic and adsorptive remediation of hazardous environmental pollutants by hybrid nanocomposites
  200. Synthesis and Characterization of PVA/Starch Hydrogel Membranes Incorporating Essential Oils Aimed to be Used in Wound Dressing Applications
  201. Hydrocarbon fuels from CO2 and H2O by molten salt electrolysis
  202. Formulation of zeolite supported nano-metallic catalyst and applications in textile effluent treatment
  203. Strength degradation mechanism of iron coke prepared by mixed coal and Fe2O3
  204. Surfactants-based remediation as an effective approach for removal of environmental pollutants—A review
  205. Evaluation and detoxification of aflatoxins in ground and tree nuts using food grade organic acids
  206. Life Cycle Costing Analysis: Tools and Applications for Determining Hydrogen Production Cost for Fuel Cell Vehicle Technology
  207. Torrefied biomass fuels as a renewable alternative to coal in co-firing for power generation
  208. Evaluation de l’effet de nutrition azotée sur la productivité de l’eau de quelques variétés de blé dur
  209. Modeling Viscosity and Density of Ethanol-Diesel-Biodiesel Ternary Blends for Sustainable Environment
  210. Kinetic and thermodynamic evaluation of effective combined promoters for CO2 hydrate formation
  211. Biocomposite of sodium-alginate with acidified clay for wastewater treatment: Kinetic, equilibrium and thermodynamic studies
  212. Adverse drug reaction monitoring and reporting among physicians and pharmacists in Pakistan: A cross-sectional study
  213. Design and optimization of electrochemical cell potential for hydrogen gas production
  214. Synthesis of 5-Fluorouracil Cocrystals with Novel Organic Acids as Coformers and Anticancer Evaluation against HCT-116 Colorectal Cell Lines
  215. Implications of advanced wastewater treatment: Electrocoagulation and electroflocculation of effluent discharged from a wastewater treatment plant
  216. Thermal and kinetic analysis of diverse biomass fuels under different reaction environment: A way forward to renewable energy sources
  217. Assessment of biomass energy potential for SRC willow woodchips in a pilot scale bubbling fluidized bed gasifier
  218. Green synthesis and biological evaluation of novel 5-fluorouracil derivatives as potent anticancer agents
  219. Experimental investigation of tar arresting techniques and their evaluation for product syngas cleaning from bubbling fluidized bed gasifier
  220. Sustainable ventilation strategies in buildings: CFD research
  221. Electrochemical investigation of novel reference electrode Ni/Ni(OH)₂ in comparison with silver and platinum inert quasi-reference electrodes for electrolysis in eutectic molten hydroxide
  222. Simulation of Particle Mixing and Separation in Multi-Component Fluidized Bed Using Eulerian-Eulerian Method: A Review
  223. Synthesis of anthraquinone-based electroactive polymers: a critical review
  224. Biological synthesis of copper nanoparticles, using Nerium oleander leaves extract: Characterization and study of their interaction with organic dyes
  225. Sustainable energy saving alternatives in small buildings
  226. Effect of Slot Wall Jet on Combustion Process in a 660 MW Opposed Wall Fired Pulverized Coal Boiler
  227. Future of 5-fluorouracil in cancer therapeutics, current pharmacokinetics issues and a way forward
  228. Catalytic performance of Cu- and Zr-modified beta zeolite catalysts in the methylation of 2-methylnaphthalene
  229. Assessment of knowledge, attitude and practice of adverse drug reaction reporting among healthcare professionals in secondary and tertiary hospitals in the capital of Pakistan
  230. Oxy-fuel combustion study of biomass fuels in a 20 kW th fluidized bed combustor
  231. Concentrating photovoltaic thermal (CPVT) collectors and systems: Theory, performance assessment and applications
  232. Experimental investigation of woody and non-woody biomass combustion in a bubbling fluidised bed combustor focusing on gaseous emissions and temperature profiles
  233. Strategies for ideal indoor environments towards low/zero carbon buildings through a biomimetic approach
  234. Study of gas-liquid mixing in stirred vessel using electrical resistance tomography
  235. Industrial polymer effluent treatment by chemical coagulation and flocculation