Bentonite blended with bagasse ash as an adsorbent for reactive red 198 dyes

Adsorption offers efficient, cost-effective, and eco-friendly method for the treatment of dye-laden wastewater. This work presents, reactive red 198 (RR198) removal by adsorption using bentonite clay (BC) blended with sugar cane bagasse ash (SCBA). The adsorbent's surface morphologies, crystalline phase structures, functional groups, and specific surface before and after adsorption were examined using SEM, XRD, FTIR, and BET respectively. Central composite design (CCD) under response surface methodology (RSM) was applied to optimize independent and dependent variable values. The optimal parameters for RR198 removal using the blended adsorbent were 107 minutes contact time, 0.934 g/L adsorbent dose, and 15 mg/L initial dye concentration, and 85.2% RR198 removal efficiency was achieved. The sorption isotherms and kinetics were evaluated using various existing models. The Freundlich isotherm model (R2 = 0.95) and the pseudo-second-order equation best described the adsorption parameters and the RR198 adsorption kinetic mechanism, respectively. Desorption and reusability experiments in batch study confirmed that BC blended with SCBA can be used multiple times for dye removal from wastewater.

Study of Adsorption Properties of Bentonite Clay

The clay used in this study was the bentonite from Mostagnem, Algeria. This material is used in many fields such as drilling, foundry, painting, ceramics, etc. It can also be applied in the treatment of wastewaters from chemical industries by means of adsorption. In this chapter the physicochemical properties of bentonite were determined by using several analyses techniques such as chemical composition, XRD, FTIR and SBET. The bentonite was intercalated by aluminum poly-cations solution and cethytrimethyl ammonium bromide. The acid activation of natural bentonite was performed by treatment with hydrochloric acid at different concentrations. The surface water pollutants removed by the modified bentonites are bemacid yellow E-4G and reactive MX-4R dyes, and fungicide chlorothalinil. The Langmuir and Freundlich adsorption models were applied to describe the related isotherms. The pseudo-first order and pseudo-second order kinetic models were used to describe the kinetic data. The changes of enthalpy, entropy and Gibbs free energy of adsorption process were also calculated.

A Review on Current Trends in Heavy Metal Removal from Water between 2000-2021

Recent fiscal growth has necessitated diverse industrial processes to meet the growing demands around the world. Toxic chemicals such as micro-pollutants, personal care products, pesticides contaminate the effluents of these industries and find their way into the environment leaving dangerous levels of heavy metals in the aquatic ecosystem. These heavy metals such as arsenic, chromium, lead, mercury, cadmium and nickel bio-accumulate and are very harmful to humans. Several water treatment methods were reviewed from 111 published articles covering a period between 2000-2021 on the progress of Heavy Metal removal from waste water including the use of low cost agro based activated carbon and Bentonite clay as part of “green and sustainable chemistry”.

Analysis of sorption capacity of natural sorbents in relation to aqueous solutions of heavy metal compounds

The main preconditions emergence of an environmental crisis in the country due to surface water pollution include irrational use of water resources in violation of the environmental requirements, discharge of untreated and insufficiently treated industrial and municipal wastewater into water bodies and inflow of polluting substances from agricultural lands as a result of surface water drainage. The whole set of considered factors leads to depletion and pollution of surface water of Ukraine, reduction of their self-cleaning capacity, degradation, impoverishment and collapse of aquatic ecosystems. Excessive content of heavy metal ions in surface water has a negative impact on the environment, causing acute and chronic diseases. Ingress of such pollutants into surface water is almost entirely due to anthropogenic economic activity. Wastewater from chemical, ferrous and nonferrous metallurgy brings a great amount of such pollutants. Among various methods used for removing heavy metal ions from aqueous media, sorption methods remain one of the most effective and popular, mainly due to the fact that they ensure a high degree of purification at relatively low costs. Along with the adsorbents traditionally involved in these processes, a number of studies and practical implementations with use of natural dispersed minerals as adsorbents were conducted lately. The research aims at studying the sorption capacity and efficiency of natural and modified sorbent such as bentonite clay for purification of aqueous solutions containing heavy metal ions in the form of dissolved compounds and justifying its potential application. It studies the efficiency of wastewater treatment aimed at removing heavy metal ions by the natural clay sorbent of bentonite clays of the Cherkaskyi Deposit (Dashukovskyi deposit). The paper presents a technique for modification of bentonite clay in order to increase its adsorption capacity for heavy metal ions using the following three methods: physical (thermal), chemical (processing with application of Iron(III) chloride solution) and combined (thermal processing of the original sorbent followed by processing with application of Iron(III) chloride solution). It has been experimentally proved that a natural sorbent modified via thermal and chemical processing is characterized by a high absorption capacity to heavy metal ions contained in water solutions, in particular to chromium(VI) ions, copper(II) ions and aluminum(III) ions with the purification degree ranging from 5% to 83%. The highest adsorption rate, 83%, is demonstrated by the combined method of bentonite clay modification, therefore proving the effectiveness of application of environmentally friendly natural sorbents for wastewater treatment processes aimed at removing heavy metal ions. The paper indicates the advantages of wastewater treatment sorption methods allowing removal of pollutants of different origin and any concentration.

Spectroscopic Studies of Polypyrrole - PVA Reinforced Iraqi Bentonite Clay Composites

The mixture of Polypyrrole solution with polyvinyl alcohol reinforced Iraqi Bentonite clay are used for preparing a composite that investigated in this study. The weight percentage of bentonite used is 5, 10, 15, and 20 and the particle size selected is less than 75 μm. Composite samples prepared has a thickness of 0.15mm and dimensions of 2.6×2.8 cm2. The optical properties of polymer composites were studied using UV-Vis spectroscopy. The values of optical energy gap decreased from 5.44, 5.41, 5.38 and 5.28 eV for the 5, 10, 15, and 20 wt% of bentonite respectively, and the absorption coefficient increased. The extinction coefficient increases with increasing additive bentonite and decreases as the incident wave length increase. The present work is very important for tailoring the optical response of Polypyrrole – bentonite composites according to specific requirements.

Bentonite Clay Mixed With Different N Sources Have Variable Effect on Nitrate Leaching From Sandy Soil

Nitrate (NO3) leaching from soils results in lower soil fertility, reduced crop productivity and groundwater pollution. The present study determined NO3 leaching from bentonite [0, 2 and 4% (m/m)] treated sandy soil, under three N sources (calcium nitrate [Ca(NO3)2], ammonium chloride [NH4Cl], urea [CO(NH2)2] @ 300 kg N ha-1) with a leaching fraction of 0.3-0.4. Bentonite markedly reduced NO3 release in leachate, while 4% bentonite retained higher NO3 in soil. The NO3 leaching varied with N sources as Ca(NO3)2>NH4Cl>(CO(NH2)2. This study indicated that soil amendment with bentonite could efficiently mitigate NO3 leaching from soil and hence prevent N fertilizer losses and groundwater pollution.