**3. Biopolymer extraction methodologies**

#### **3.1. Extraction of the plants** *Melocactus* **sp.,** *Opuntia dillenii***,** *Stenocereus griseus***,**  *Cereus forbesii***,** *Aloe arborescens***, and** *Aloe vera*

The extractions of each plant have particularities, taking into account the usable parts in the search of their coagulating capacity. The extractions are segregated into two types: the plants that are used in all their foliage are *Melocactus* sp. (**Figure 4**), *Opuntia dillenii* (**Figure 5**) [9], *Stenocereus griseus*, *Cereus forbesii*, being belonging to the family Cactaceae and the other part corresponds to *Aloe arborescens* and *Aloe vera*, belonging to the Xanthorrhoeaceae family, with superior *Aloe* classification.

For the *Cactus* and *Aloe* species, an extraction methodology was used with different opera-

**Figure 4.** *Opuntia* sp. Source: http://www.fichas.suculentas.es/Almacenfichas/903/903.html.

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**Figure 5.** *Aloe vera*. Source: http://www.fichas.suculentas.es/Almacenfichas/903/903.html.

• Selection of parts of the plant for cutting: The operation of cutting parts of the plant is done taking into account mature parts, with the presence of thorns in the case of cacti, with a hard external surface, similar to the criteria used for the animal or human consumption of

tions that are:

**Figure 4.** *Opuntia* sp. Source: http://www.fichas.suculentas.es/Almacenfichas/903/903.html.

The selected plants took a part of those referenced and others of those present in semiarid regions in Colombia, such as La Guajira in northern Colombia and the banks of the Chicamocha River, in the northeastern region. The species not studied are *Stenocereus griseus* (**Figure 1**), *Cereus forbesii* (**Figure 2**), *Aloe arborescens*, and *Aloe vera*; and one already studied is

In the case of *Opuntia* sp., they are used to be present in the Colombian regions already named and sufficiently studied, in the same way *Aloe vera* and *Aloe arborescens* were selected (**Figure 3**). Kabuli chickpea (*Cicer arietinum*) is reviewed with studies already elaborated by other authors [7]. It should be noted that some species of *Opuntia* spp. are used as part of the animal and human diet in communities of northeastern Colombia, in semidesert areas [8].

To have a better selection, we reviewed the massive presence of these plants and that they were not part of the list of plants in danger of extinction, to be able to access their manipulation.

The extractions of each plant have particularities, taking into account the usable parts in the search of their coagulating capacity. The extractions are segregated into two types: the plants that are used in all their foliage are *Melocactus* sp. (**Figure 4**), *Opuntia dillenii* (**Figure 5**) [9], *Stenocereus griseus*, *Cereus forbesii*, being belonging to the family Cactaceae and the other part corresponds to *Aloe arborescens* and *Aloe vera*, belonging to the Xanthorrhoeaceae family, with

**3.1. Extraction of the plants** *Melocactus* **sp.,** *Opuntia dillenii***,** *Stenocereus griseus***,** 

the Kabuli chickpea (*Cicer arietinum* L.) [6].

**Figure 3.** *Aloe arborescens*.

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**3. Biopolymer extraction methodologies**

*Cereus forbesii***,** *Aloe arborescens***, and** *Aloe vera*

superior *Aloe* classification.

**Figure 5.** *Aloe vera*. Source: http://www.fichas.suculentas.es/Almacenfichas/903/903.html.

For the *Cactus* and *Aloe* species, an extraction methodology was used with different operations that are:

• Selection of parts of the plant for cutting: The operation of cutting parts of the plant is done taking into account mature parts, with the presence of thorns in the case of cacti, with a hard external surface, similar to the criteria used for the animal or human consumption of *Opuntia* spp. [10]. In the case of *Aloe* species, the maturity of the leaves is considered, with the presence of perimeter spines. This shows the possibility of isolating the crystals of the plant.

**Figure 5** shows a part of the penca or cladodes of a cactus *Opuntia* sp., with skin and thorns, but the part to be used is the vascular tissue of the plant, eliminating skin and spines [11].

For the sampling of the species of *Aloe* (**Figure 6**), garden plants were considered, which are cultivated in a homemade way, taking into account the age of the plant, as it must have enough leaves with enough crystals, and it must not present any evidence of contamination or parasites, especially the characteristics of the green color of the leaves, absence of external insects, and total absence of organisms associated with diseases of the plant.


called epidermis, which is the external hard part of the pads or cladodes, in the case of

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• Cutting of clean material: In order to follow the extraction process, the tissue of the plants is cut. This is done to improve the moisture loss of the plant, increasing the contact surface

cactus and leaves in the case of *Aloe* species.

**Figure 7.** *Opuntia* sp. and *Cereus forbesii* samples. Source: authors.

with the atmosphere (**Figure 9**).

**Figure 8.** Removal of thorns. Source: authors.

**Figure 6.** *Melocactus* sp. Source: http://www.tephroweb.ch/kuas/melo.htm.

**Figure 7.** *Opuntia* sp. and *Cereus forbesii* samples. Source: authors.

*Opuntia* spp. [10]. In the case of *Aloe* species, the maturity of the leaves is considered, with the presence of perimeter spines. This shows the possibility of isolating the crystals of the plant. **Figure 5** shows a part of the penca or cladodes of a cactus *Opuntia* sp., with skin and thorns, but

For the sampling of the species of *Aloe* (**Figure 6**), garden plants were considered, which are cultivated in a homemade way, taking into account the age of the plant, as it must have enough leaves with enough crystals, and it must not present any evidence of contamination or parasites, especially the characteristics of the green color of the leaves, absence of external insects, and

• Cut and transport to the laboratory: The cutting of the parts of the plant takes measurements (**Figure 7**), to then make a transport to the site of obtaining the coagulant. The transport must be carried out in refrigeration, to avoid possible contamination with environmental fungi or other organisms that can significantly change the composition of the parts obtained. • Weighing of the gross material: The weighing of the material is carried out on a 25-kg scale, to determine the weight of the sample taken and then determine its performance according

• Cutting of thorns and removal of the bark: To perform the extraction of the coagulant, the cut parts are taken and the thorns are removed (**Figure 8**), and the skin of the cacti, also

the part to be used is the vascular tissue of the plant, eliminating skin and spines [11].

total absence of organisms associated with diseases of the plant.

**Figure 6.** *Melocactus* sp. Source: http://www.tephroweb.ch/kuas/melo.htm.

to its humidity.

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**Figure 8.** Removal of thorns. Source: authors.

called epidermis, which is the external hard part of the pads or cladodes, in the case of cactus and leaves in the case of *Aloe* species.

• Cutting of clean material: In order to follow the extraction process, the tissue of the plants is cut. This is done to improve the moisture loss of the plant, increasing the contact surface with the atmosphere (**Figure 9**).

• Drying the pieces: The drying of the material is carried out outdoors (**Figure 10**). It is important to note that the region in which these operations are carried out is of a warm tropical climate with low humidity, in which the temperature ranges between 20 and 35°C with relative humidities between 50 and 70% on average.

The final characteristics of the material are similar to the raw materials used in the coagulation and flocculation process, that is, a presentation similar to the presentation of type A and B aluminum sulfate and aluminum polychloride, in their solid presentations, the liquid presentation is not sought because it is an organic material with nutritional characteristics for filamentous fungi and bacteria, which would require a procedure for its sterilization, and any application of excessive heat, a degradation of the biopolymers will be carried out, condition

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• Material screening: The material after being macerated is taken to a 1-mm sieve (**Figure 11**), which separates the thick parts that cannot be diluted efficiently in aqueous solution. This characteristic is based on the solubility of complex organic substances, such as the vascular

• Weighing of the material of interest: The material obtained from the plants *Melocactus* sp., *Opuntia dillenii*, *Stenocereus griseus*, *Cereus forbesii*, *Aloe arborescens*, and *Aloe vera* is weighed to have a reference of its performance in relation to weight to weight, with respect to its use.

The seeds of the anionic coagulant Kabuli Garbanzo (*Cicer arietinum* L.) were selected and

• Washed: The seeds selected without evidence of the presence of fungi or yeasts were washed with large amounts of water to eliminate impurities related to bulk handling and then in their fractionation and packaging that can take other materials such as small sand

that impairs its performance in coagulation.

tissue of these cacti and *Aloe* plants.

then the following procedures were performed.

stones or other grain waste.

**Figure 11.** Maceration of the material. Source: authors.

**3.2. Extraction of Kabuli chickpea coagulant (***Cicer arietinum* **L.)**


**Figure 9.** Cutting of the plants. Source: authors.

**Figure 10.** Desiccation of the specimens. Source: authors.

The final characteristics of the material are similar to the raw materials used in the coagulation and flocculation process, that is, a presentation similar to the presentation of type A and B aluminum sulfate and aluminum polychloride, in their solid presentations, the liquid presentation is not sought because it is an organic material with nutritional characteristics for filamentous fungi and bacteria, which would require a procedure for its sterilization, and any application of excessive heat, a degradation of the biopolymers will be carried out, condition that impairs its performance in coagulation.


#### **3.2. Extraction of Kabuli chickpea coagulant (***Cicer arietinum* **L.)**

• Drying the pieces: The drying of the material is carried out outdoors (**Figure 10**). It is important to note that the region in which these operations are carried out is of a warm tropical climate with low humidity, in which the temperature ranges between 20 and 35°C

• Weighing of dehydrated material: The material is kept outdoors, taking care that it is not hydrated by rain, the drying time is between 48 and 96 h depending on the temperature

• Grinding of the material: The grinding of the dried material is done with a food processing

device and then it is passed through a mill that pulverizes the material.

with relative humidities between 50 and 70% on average.

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and relative humidity of the place where they are dried.

**Figure 10.** Desiccation of the specimens. Source: authors.

**Figure 9.** Cutting of the plants. Source: authors.

The seeds of the anionic coagulant Kabuli Garbanzo (*Cicer arietinum* L.) were selected and then the following procedures were performed.

• Washed: The seeds selected without evidence of the presence of fungi or yeasts were washed with large amounts of water to eliminate impurities related to bulk handling and then in their fractionation and packaging that can take other materials such as small sand stones or other grain waste.

**Figure 11.** Maceration of the material. Source: authors.

• Drying: After washing, it was dried for 2 days in the sun, taking into account that they cannot be wetted by rain or other water source.

The control parameters normally used in the efficiency of a coagulant are pH, turbidity, and color, which are governed by standardized methodologies [13], which determine the ability to remove solids from water based on their behavior, pH, and with its spectrophotometric

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In accordance with the regulations in force in Colombia, the tests were carried out taking into

The removal obtained is processed in terms of percentages, to be able to compare. In the case of pH, it is observed that it complies with the provisions of the national standard for this parameter [15]; and in the case of turbidity and color, the percentage of removal is taken into

The results of the tests of the biopolymers, natural coagulants, are collected in four main tests, the first ones refer to the pH, the turbidity, and the color; the last one takes the coagulants

Turbidity and color in water is related to the presence of substances or microorganisms, which is directly related to its quality to be consumed or used in other ways; the results offer an overview of the potentialities of all the plants for the coagulation and flocculation processes,

To control the efficiency of coagulation and flocculation as a function of pH, the pH was taken after coagulation, taking into account that the initial pH of the water is 7.2. The pH results are shown in **Graph 1**, showing that the coagulant that most affected the final pH was the biopolymer of *Melocactus* sp., which brought the pH up to 6.2. The data show a standard

**Graph 1** shows that the only one that did not affect the pH in the jar test was *Stenocereus* spp.;

The turbidity results (**Graph 2**) showed that the best biopolymers to remove these solids associated with turbidity were *Melocactus* spp. and Kabuli chickpea (*Cicer arietinum* L.), which showed turbidity removals greater than 95 and 97%, respectively. The data show a standard

The results of the other biopolymers showed a removal capacity greater than 88 and up to 92%, which shows the effectiveness of these biopolymers with water that has a neutral pH.

All the biopolymers tested showed effective action in the removal of turbidity, in a range between 88 and 97%, with some differences and affectations to the pH of the sample at the

For the case of the color results (**Graph 3**), we can see a good activity of all the biopolymers, taking into account that the one that showed the best performance in the removal of the

absorbance, turbidity and color at different wavelengths.

with good performance and measures the Z potential.

the others lowered the pH moderately to values of 7 or 6.8.

with different degree of efficiency.

deviation of 0.3.

deviation of 3.1.

final moment of the jar test.

account the technical standards adopted by the country for each test [14].

**5. Results of jar tests with natural coagulant biopolymers**

account, which is directly proportional to the decrease in absorbance in each test.

• Crushed: The material was crushed using a mixer (Oster). The resulting powder was sieved with a No. 200 sieve to obtain a very fine powder for storage in plastic containers to avoid hydration and subsequent use in the preparation of the solutions of the coagulant.
