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In this study, lupine seed (Lu-SP) and pumpkin seed shells (PSSP) biomasses were used to create alternative and effective adsorbents. Methylene blue (MB) dye was removed from wastewater using the as-prepared adsorbents at variables solution pH 2.0 –11.0, contact period (0–180 min), and adsorbent mass (0.2–2.0 g/L). The solution pH had a synergistic effect on the improved removal of MB and the optimal adsorption removal for both adsorbents occurred at pH 8.0 and 120 min. The adsorption isotherm modelling results showed a good fit with the Langmuir model, with a maximum monolayer adsorption capacity of 48.98 and 77.48 mg/g for PSSP and Lu-SP, respectively. Similarly, the pseudo-first-order (PFO) model is regarded as the best-fit kinetic model for both adsorbents and suggests the predominance of physisorption via interfacial diffusion. Mechanistic investigation of the present system suggests that both intraparticle diffusion and surface sorption mechanisms control the adsorption rate. Notably, the Lu-SP with a lower surface area (54.013 m2/g) outperformed the PSSP (235.992 m2/g) in terms of adsorption capacity under varying pH. Therefore, in addition to electrostatic interaction, adsorption into the micropores via volume filling is considered one of the adsorption mechanisms. This study, therefore, revealed that the PSSP and Lu-SP may be very helpful for removing cationic MB dye from contaminated wastewater.

The study explored the capacity of modified pinewood dust (S-dust) for adsorbing acid blue 193 dye. The novel adsorbent was prepared via the insitu intercalation of quaternized ammonium copolymer (cationic surfactant) onto pinewood dust. The synthesized biosorbent was characterized using the Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM), Energy Dispersion X-ray (EDX) and Brunauer–Emmett–Teller (BET) surface area equipment. To establish the variable effects on the dye uptake, the ranges of solution pH, initial adsorbate concentration, contact time and adsorbent dosage were varied. The maximum monolayer adsorption capacity of 117.58 mg/g was recorded at pH 4.0, 0.1 g/L adsorbent dose and 2 h sorption duration. The process kinetics and isotherm modelling fitted best to the pseudo-first-order and Freundlich models, respectively. From the mechanistic/diffusion studies, intraparticle and pore diffusion mechanisms were respectively postulated at low and high initial adsorbate concentrations. Also, the occurrence of a nonspontaneous endothermic uptake process was inferred from the thermodynamics evaluations. Therefore, the effective acid blue 193 dye uptake onto novel S-dust was confirmed in this study.

This study focuses on the adsorptive removal of metronidazole (MET) antibiotics from wastewater using a cellulose-chitosan composite (Ce–C). The composite was synthesized through an in-situ adsorption mechanism, with glutaraldehyde as a crosslinking agent. The Ce–C composite exhibited a swelling capacity of 3.2 mL/g and a BET surface area of 110.53 m2/g. The batch adsorption isotherms revealed a maximum monolayer adsorption capacity of 14.32 mg/g, with the Langmuir model providing the best fit. Kinetic analysis indicated that the pseudo-first-order model best described the adsorption process. The Ce–C composite also demonstrated biodegradability, with a 79.31% mass loss over 25 days, an indication of the eco-friendliness of the composite. The findings suggest that the Ce–C composite is an effective and eco-friendly adsorbent for MET removal from wastewater.

This study investigated the application of artificial intelligence algorithms (AIA) in the coagulation treatment of paint wastewater anchored by novel Phaseolus vulgaris seed extract (PVSE). Untreated wastewater discharge harms the ecosystem, and therefore harmful industrial effluent, such as paint wastewater, must be brought to safe discharge levels before being released into the environment. In addition to AIA, comprehensive characterization tests, coagulation kinetics, and process optimization were also executed. Characterization results revealed that total solid in the PWW was above allowable standard, justifying the need for effective particle decontamination. The XRD and FTIR characterization indicated that PVSE structure is amorphous with abundant amine groups. Results of analysis of variance (ANOVA) obtained from process modeling indicated that the coagulation-flocculation process was a nonlinear quadratic system (F-value = 45.51) which was mostly influenced by PVSE coagulant dosage (F-value = 222.48; standardized effect = 14.85). Artificial intelligence indicated that neural network training effectively captured the nonlinear nature of the system in ANN (RMSE = 0.00040194; R = 0.98497), and ANFIS (RMSE = 0.003961) algorithms. Regression coefficient obtained from process modeling highlighted the suitability of RSM (0.9662), ANN (0.9739), and ANFIS (0.9718) in forecasting the coagulation-flocculation process, while comparative statistical appraisal authenticated the superiority of ANN model over RSM and ANFIS models. The coagulation kinetics experiment, which used a coagulation kinetic model, revealed a constant flocculation constant (Kf-value) for all jar test batches and a strong association between the Menkonu coagulation-flocculation constant (Km) and Kf values. Best removal efficiency of 97.01 % was obtained using ANN coupled genetic algorithm optimization (ANN-GA) at PVSE dosage of 4 g/L, coagulation time of 29 min and temperature of 25.1oC.

In this study, Aspergillus oryzae (A. Oryzae) biomass and waste peach seed shells (PPSS) were used to create alternative and effective adsorbents. Acid Violet 90 (AVD) dye was removed from wastewater using the as-prepared adsorbents. Different process variables like pH (2–11), contact period (0–180 min), and adsorbent mass (0.2–2.0 g/L) were examined. The solution pH had a synergistic effect on the improved removal of AVD and the optimal adsorption removal for the PPSS and the A. Oryzae adsorbent occurred at pH 2.0 and pH 5.0, respectively. The findings demonstrated that, in comparison to A. Oryzae, PPSS reported a greater AVD adsorption (mg/g). The equilibrium time for the adsorption process was attained within 180 min for both adsorbents. The adsorption kinetics modelling results showed a good fit with pseudo-second-order kinetics, for both adsorbents, with average R2 values of 0.999 (for PPSS) and 0.997 (for A. Oryzae). Similarly, the isotherm modelling results confirmed the good fitting of the Langmuir isotherm model for A. Oryzae (R2 = 0.999) and the Freundlich model for PPSS (R2 = 0.997). The maximum adsorption capacity (qmax) of 55.0 and 94.92 mg/g was recorded for A. Oryzae and PPSS, respectively. Mechanistic investigation of the present system suggests that both intraparticle diffusion and surface sorption mechanisms control the adsorption rate. As agro materials, both adsorbents are composed of mostly oxygen-based surface functional groups like the –OH, –C = O, -C-O-C, and multiple carbon-carbon bonds, all contributed to the synergistic mechanism interaction between the adsorbent and AVD dye in this study. This study, therefore, revealed that the PPSS and A. Oryzae may be very helpful for removing anionic dye from contaminated wastewater, indicating its potential for useful application in the removal of other major pollutants.

In this study, the effectiveness of C. schweinfurthii biochar (CSSB) for the adsorption of aqueous crystal violet dye (CVD) was investigated. Batch mode experiments were conducted to examine the influence of different process variables on the dye adsorption capacity of the CSSB. The surface chemistry and morphology of the adsorbent were elucidated using the Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy/energy dispersion X-ray (SEM/EDX), respectively. At optimum adsorption conditions (50 mg/L adsorbate concentration, 303 K and 35 min), a maximum removal efficiency of 90.04% was achieved. The experimental equilibrium and kinetic data were best fit to the Freundlich isotherm and Elovich kinetics models, respectively. The thermodynamic evaluation showed average Gibbs free energy (ΔGo), entropy change (ΔSo) and enthalpy change, (ΔHo) values of −1647.18 KJ/mol, −58.69 KJ/mol K and −173.10 KJ/mol, respectively. These thermodynamic data demonstrated that CVD adsorption onto CSSB was favourable, spontaneous, and exothermic. Any doubts about the adsorbent's economic viability were allayed by its projected cost of 0.0003 USSD/g per gram of adsorbate. Thus, according to the experimental results, the CSSB is considered an economical, effective, and environmentally friendly adsorbent for aqueous CVD adsorption.

This paper reports the adsorption of methyl blue dye onto a quaternized starch derivative (S-Quat) from an aqueous solution. The starch derivatization was achieved via the reaction between (3-chloro-2-hydroxypropyl) tri-methyl ammonium chloride (Quat-188) and maize starch in the presence of aqueous sodium hydroxide. Various instrumental characterization techniques were deployed to confirm the presence of important functional groups, crystalline structure and surface texture/morphology, which played key roles during the dye uptake. The Brunauer–Emmett–Teller (BET) surface area and pore size of the S-Quat were recorded as 41.328 ​m2. g−1 and 1.763 ​nm, respectively. The effect of solution pH, contact time and adsorbent concentration on the adsorption capacity of the S-Quat were examined via batch mode. Maximum adsorption of ∼260 ​mg/g was achieved at pH 2.0 ​and 75 ​min contact time. Furthermore, the kinetic data modelling showed that the Fractional power, Brouser–Weron–Sotolongo (BWS), and Fractal-like PFO (FPFO) models, respectively, were the top three models of best fit. Thus, the quaternized starch derivative (S-Quat) showed good dye adsorption potentials.

The pollutant binding capacity of amino functional groups has been widely documented. In this study, abundant amino groups were added onto acrylic fibre via functionalization with 1,2-diaminoethane to yield acrylic fibre-based hydrogel (Ac-EDA). The Ac-EDA was further applied for the adsorptive uptake of lead ions. The successful attachment of amino groups on the fibre was verified from the fourier transform infrared spectroscopy and scanning electron microscopy-energy dispersive x-ray, SEM-EDX results. The study on the effect of process variables highlighted a pH non-responsive sorption, due to the non-electrostatic interaction between the basic nitrogen atom of the amino groups and the lead ion. The Langmuir maximum adsorption capacity of 371.26 mg/g was recorded at optimum process conditions. The adsorption modelling emphasized the predominance of internal diffusion as the rate-limiting step. This study showed the effectiveness of the Ac-EDA for the uptake of aqueous lead ions.

In this study, microbially synthesized biosurfactants were immobilized on mesoporous activated carbon and the biocomposites were further utilized for chromium removal from petroleum refinery wastewater. Due to the acidic and lactone rings on the E. coli biosurfactant, which confers improved hydrophilicity, the activated carbon functionalized with E-coli biosurfactant (EB-Zn/AC) depicted better chromium adsorption than the sophorolipid functionalized activated carbon (SB-Zn/AC). Hence, at 240 min, pH 8.0 and biocomposite concentration of 6.0 g/L, a maximum adsorption efficiency of 99.60% and 53.98 was recorded for EB-Zn/AC and SB-Zn/AC, respectively. The isotherm and kinetic data correlated best with Freundlich and pseudo-second-order models, respectively for both biocomposites, with their coefficient of determination (R2) value greater than 0.9 in all cases. Thermodynamic parameters show that the process was feasible and spontaneous. The post adsorption water sample characterization result shows that the chromium ion concentration was brought within EPA (Environmental Protection Agency) wastewater discharge standard.

Due to their high seed protein content (36 to 42% of the dry weight), lupine seed serve as a valuable nutritional source for low-income populations. Unfortunately, the high protein content which makes them highly desirable also turns them into food allergens, thus justifying its alternative application as an adsorbent. Therefore, this study explored the potential of lupine seed powder (L-SP) as a novel, efficient and low-cost adsorbent for the uptake of acid blue 193 dye. The adsorption process was evaluated via batch mode, under the influence of several process variables (such as initial dye concentration, 10–100 mg/L; temperature, 30 – 70 °C; adsorbent dosage, 0.2 – 3.0 g/L; solution pH, pH 2.0 – 10.0 and contact time, 1 – 180 min). The structural and morphological characteristics of the l-SP adsorbent, as well as its elemental composition, was elucidated from the Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy dispersion X-ray (EDX) analyses. A maximum adsorption capacity of 144.56 mg/g was obtained at 25 °C. The thermodynamic investigation suggests a prevailing endothermic process, thus adsorption is enhanced at an increased degree of freedom between the adsorbent and adsorbate solution interface.

Amidoximated biosorbent (oximated MT) was successfully synthesized from manna tree (Alhagi Graecorum) residue and subsequently applied for the adsorption of aqueous lead ions. The oximated MT was obtained from tri-synthesis steps of dried residue pulverization, polymerization and nitrile amidoximation. The synthesized adsorbent was effectively characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy dispersion x-ray (EDX) measurements. An optimum adsorptive uptake was established at a contact time of 45 min, pH 6.0, and 0.03 g/L adsorbent dosage. The experimental isotherm and kinetic data were best fitted to the Temkin and Elovich models, respectively. Furthermore, the “approaching equilibrium factor” (RE) value of the Elovich model suggests the occurrence of a mildly rising curve, since 0.1 < RE< 0.3. The mechanistic investigation reveals the predominance of pore and intraparticle diffusion mechanism at low (200 mg/L initial adsorbate concentration) and high (400 & 600 mg/L initial adsorbate concentrations), respectively. Furthermore, the thermodynamic study suggests a prevailing endothermic process.

An ideal adsorbent must be relatively cheap, abundant, easily undergo modification, and exhibit better removal efficiency. Animal wastes are much better adsorbents in comparison with activated carbon adsorbents with respect to being cost-effective and their zero regeneration process factor. The review aims to report the efficiency of utilized cow-dung based adsorbents for the sequestration of a wide spectrum of pollutants from aqueous media. It discusses the potential of utilizing cow dung as a cheap and effective adsorbent. It was observed that cow dung-based adsorbents were efficient for the removal of dyes, heavy metals, and other pollutants from aqueous solutions. The maximum reported uptake capacity of dyes and heavy metals was 501 ​mg/g and 625.26 ​mg/g for Methylene blue and lead, respectively, which were both for cow dung activated carbon. The Langmuir and Freundlich isotherm models emerged as the best-fit models for almost all studies. Based on the review outcome, a pseudo-second-order model was reported as the kinetic model of best fit in all cases. Other adsorption studies such as adsorption mechanism, thermodynamic modelling, desorption, column adsorption, and competitive adsorption were also included in this study. Finally, the study identified some knowledge gaps that could aid future investigation in this research field. Summarily, it can be deduced that cow dung-based adsorbent has exhibited good potential as an adsorbent for the mitigation of pollutants from water.

This study reports the synthesis of a superabsorbent hydrogel (HS) through the polyacrylonitrile (PAN) graft copolymerization and subsequent hydrolysis of corn starch. The surface morphology and chemistry, as well as the physicochemical characteristics of the hydrogel, were elucidated. The effectiveness of the synthesized hydrogel sorbent for remediating a basic blue-9 dye contaminated stream was subsequently investigated. Also, the relationship between the different process variables and the hydrogels’ remediation (sorption) capacity was studied, while the generated experimental kinetic and equilibrium data were effectively modelled using relevant isotherm and kinetic models. The Langmuir isotherm and pseudo-first-order kinetic models fitted best to the equilibrium and kinetic data, respectively. By applying specified mechanistic models, the intraparticle diffusion mechanism was identified as the sole rate-limiting step of the sorption process. The hydrogel showed excellent water absorption and monolayer sorption capacities of 710 ±1.6 g water/g and 343.27 ±1.3 mg/g, respectively. Thus, the hydrogel shows potential for the decontamination of dyestuff polluted streams.

The Scopulariopsis brevicompactum fungal biomass (SFB) was applied as an adsorbent for the uptake of aqueous lead species via the dynamic sorption process. The adsorption capacity dependence on the solution pH, contact time, initial adsorbate concentration and adsorbent concentration was investigated via batch mode. According to the experimental findings, the adsorption capacity was favoured by an increase in all the aforementioned process variables except adsorbent concentration. The optimum adsorption capacity was recorded at pH 6.0, 120 min, and 0.2 g/L adsorbent concentration. The process isotherm was explained by the D-R model, with predominated physisorption (E = 0.069 kJ/mol), while the pseudo-second-order model explained the process kinetics. The characterization results confirmed the presence of several metal-binding functional groups on SFB. Furthermore, by applying the mass transfer factor model, the dependence of the lead ions adsorptive mass transfer on the film diffusion regime was established. Thus, the adsorptive performance of the SFB was demonstrated in the study.

Fungal biomass, Aspergillus terricola, was synthesized and employed for the biosorption of aqueous hexavalent chromium via batch technique. Insight into the nature of the surface chemistry and morphology of the fungal biomass was obtained via infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analyses, respectively. Also, the effect of selected process variables on the Aspergillus terricola biosorption capacity was elucidated. By employing isotherm and kinetic of varying parametric equations, the study investigated the effect of the number of parameters in a given model equation on their modelling performance. Marczewki-Jaroniec (4-parameter) and Fractal-like Pseudo-first order (3-parameter) model emerged as the best fit for isotherm and kinetics studies, respectively. The finding demonstrated the dependence of modelling accuracy on the inherent number of parameters of a given model. Meanwhile, the result of the mechanistic studies highlighted the superiority of the film diffusion mechanism during the hexavalent chromium biosorption, with a Langmuir maximum adsorption capacity (q max) of 87.3 mg. g-1. Notably, the biosorption efficacy of Aspergillus terricola biomass was succinctly demonstrated in the study.